 So here is a make sure you got quiz two version two I Made this up in a real hurry. I'm not completely positive that all of the answers worked out. Okay, so we'll see how this goes Once again name. Okay for the joke Cirquee she gets everything right all the time Assuming these two figures are similar that means they're the same shape Find the missing measurements. I'm gonna give you some kind of a shape on your test It may even be the same one. I may go with a different jagged thing What you have to do Nikki first of all is somewhere there are two sides one from each shape I'll call this big shape and small shape so that I you know We're talking there must be a side in the big shape that I also know in the small shape And I notice it's this one in this one. These are the two that I know That's going to be my conversion factor In fact, my conversion factor is going to be big shape over small shape 11 over 5 equals W Natasha w is it in the small shape or in the big shape is 5 in the small shape or in the big shape So I better put the w on the bottom small shape on the bottom small shape on the bottom What does w match with in the big shape Natasha? How do I solve one of these cross multiply W is gonna be 5 times 12 and Then you would divide by 11 to get the w by itself It's gonna be 60 divided by 11, which is not going to work out evenly I think I said to you last time if it doesn't work out evenly unless I say different Emma go to two decimal places So it's gonna be 60 divided by 11 5.4545 45 First of all, it's not 5.4. I would take a half mark off for that 5.5 I've lived with but I said to go to two decimal places. Okay, this one we are marking this one We are counting so make sure you're marking your own and be honest Please all you're doing is cheating yourself if you cheat yourself X equals. Okay, let's see Oh, I'm still gonna use the same conversion factor the two sides whose pair the pair of sides that I know I know that the 11 and the 5 go together big over small X In the small triangle so Tanner it's gonna go in the small triangle on this in the small triangle in the small shape goes on the small shape and X goes with what Tanner? Once again cross multiply and solve X is gonna be 5 Times 15 and I'd have 11 X to get the X by itself. I divide by 11 Then 5 times 15 divided by 11. I get 6.82 Again, I'm taking a half mark off and I'm saying learn to round off properly Again, I'll take that right now on the test. I'm probably gonna say go to two decimal places Okay, right Remember when you're looking at your calculator answer think about don't just write it down You got to think if I'm rounding off. What's next to the one eight becomes two right Joel? What's the next one? Yeah Sorry cuz I asked you to Why cuz I asked I'll never get tired of that joke So letter Y Those of you that were away you can decide if you want to write this down Or if you want to watch and then just for practice on your own try the quiz at home Watch the video and market yourself. I'm gonna put an omit next to your score So it won't raise or lower your score those four of you that were away It might in that you didn't get a chance to get your mistakes out of your system before the test That's really what the quizzes are for I've always said the more you get wrong on the quizzes the better Cuz you probably won't get the same mistake twice in a row In theory so I'm still gonna use the same conversion factor here Joel It's gonna be big shape over small shape Y is in the big shape since the big shape is on top. I'll put the big shape on top Joel, what does Y go with in the small shape? Okay Again, it's gonna be cross multiply. Have I mentioned lately that cross multiplying is one of the most useful skills Oh it is You're gonna get Y equals 2.5 Times 11 and then you would divide by 5 to get the Y by itself I'm not showing that step because I'm trying to get this all on one screen 2.5 come in try that again 2.5 times 11 divided by 5 and I get 5.5 Even well to one decimal place How about Z? Let's see. I'm still gonna use the same conversion factor 11 over 5 And Z is in the big shape big shape on top big shape on top Z goes with 4 So Z is gonna be 11 times 4 divided by 5 It's going to be 11 times 4 close this get out of the way divided by 5 44 divided by 5 8.8. Is that right folks? Four sides four marks one mark each give yourself a little score out of four and If you got four out of four, I insist you put a little happy face right there Give yourself a score at the bottom of the page out of four if you want to it'll help you add stuff up later next page So complete the following chart assume the shape is a rectangle I'm gonna go a little faster last class. I did a long explanation So those five of you that were away last class watch the video I went through this whole chart in detail here I'm just gonna go through the answers a bit quicker and then I'll take questions afterwards Original perimeter is gonna be two times nine is 22 Original area is gonna be 18 Linear scale factor is five So perimeter scale factor is gonna be five area scale factor is gonna be 25 or 25 to 1 new dimensions are gonna be times 5 10 by times 5 45 new perimeter is gonna be 110 new area is gonna be 450 Is that right folks? I did that all on my head. So Zach here's how I'm gonna mark this This line is worth two marks a half mark off for each square that is incorrect So what you're gonna do is give yourself a little out of two right here One two three four five six, there's seven blanks So if you get four of those blanks wrong, sorry, you're gonna get zero on this row perimeter eight thirty six Area seventy two a four to three conversion factors. So to find that it's gonna be six times four divided by three eight by Well times four divided by three Sixteen that's your new dimensions new perimeter sixteen plus eight is twenty four times two forty eight Think new area eighteen times six is gonna be eighty plus forty eight is gonna be Hundred and twenty eight is the new area hundred and twenty eight. Whoo. Whoo. I'm on a roll Mr.. Do it conversion factor or perimeter scale factor is the same as the linear four to three or four over three Area scale factor is gonna be sixteen over nine or sixteen colon Same idea out of two half mark off for each square that's wrong Original rectangle was five by ten perimeter is gonna be thirty area is gonna be Fifty ooh a little trickier now. They didn't give me the linear scale factor Well a five became a twenty five a ten became a fifty What did I multiply by what is my linear scale factor here five to one? New perimeter is a hundred and fifty New area is six hundred and twenty five Yes, whoo. No, what's the new area? One thousand two hundred and fifty that's what I said can't you read okay? Where'd I get six twenty five from wow do it? Oh Perimeter scale factor same as the linear Five to one area scale factor twenty five or twenty five to one or twenty five colon way Again out of two Oh New dimensions the linear scale factor is two or two to one Which means I must have started out with a ten by twenty two to end up with a twenty by forty four Ten by twenty two will have a perimeter of sixty four Ten times twenty two is going to be two hundred and twenty Hundred and twenty eight Eight hundred and eighty two to one and Four to one Oh, they gave me the area scale factor. So now we're going backwards now I'm going to remember the stupid rhyme area square ya if I go from linear to area. I square it How do I go backwards from area to linear? I don't square it. What's the opposite of squaring? Square rooting so it's going to be the square root of that it's going to be Eight to one. Oh, I can do the original perimeter ten original area six Eight to one so two times eight sixteen by three times eight twenty four New perimeter is going to be eighty No, yes New area six times sixty four three hundred and sixty and twenty three hundred and eighty four Whoo-hoo. I'm back. I Fell off the horse here. Hello fell off the horse here, but I got right back on here and perimeter is always the same as linear Not two to one mister do it. How about eight to one read your own writing? 49 to one means my linear was seven to one square root going backwards 42 by 49 if I multiplied all those by seven I must have started out with a six by seven Which means I have a perimeter of 26 and an area of 42 and a new perimeter of 42 and 49 42 and 50 would be 82 so 80 a hundred and sixty two No 42 plus 49 is 91. Mr. Do it 182 Horse almost bucked me off, but I stayed in the saddle Area holy schmole 42 times 42 times 50 would be 22,000 I'm gonna go 2058 am I right whoa mr. Dweck Okay, uh perimeter scale factor seven to one Come on a minute party was impressed there. I went 42 times 49 on my head I cheated I went 42 times 50 and then subtracted 42 because it's one less than that my 50 times table that I can do oh No, no, no the dance was so bad that it approached goodness. Let's be clear Again out of two again out of two again out of two last one. Well, let's do the perimeter in the area perimeter is gonna be What is it gonna be there at 60? Area is gonna be 144 No Mr. Dweck I tried to do that one from memory Terrible, I guess I don't know my 12 times table as well as I thought Area of 4 to 9 or 4 over 9 or 4 9 Must have been a linear of 2 to 3 or 2 over 3 square root square root Which means the new dimensions take these times by 2 divide by 3 12 So to find two-thirds of a number it's literally 12 times 2 Thirds this is what I do like the graphing calculator because instead of a divided by puts a slash there But I am just hitting my divided by key 8 by 18 times 2 divided by 3 see if I can pull this one off in my head 12 8 by 12 is gonna have a perimeter of add them together double 40 That's gonna have an area of 8 times 12 12 times 8 is gonna be 80 plus 60 96 and The perimeter scale factor is the same as linear 2 to 3 so give yourself a score on that question out of 14, please and Again, if you got 14 out of 14 And again if you're stuck I'm because I'm not explaining how I'm getting all these answers hit me up later Or I think last day I went into each one of these up more detail watch the video online You don't know where they are. This might be a good time to ask Number three says complete the following chart linear scale factor three to one surface area is nine to one square What was the rule for volume? You didn't square it. What do you do for volume? Cube it and you know how I remember that I just remember it's the next one up from square to be honest I've got a stupid rhyme or I know area square area volumes the next big odd What comes after a two cubed so it's going to be 27 to 1 Half mark for each of those 5 to 2 is going to be 25 to 4 it's going to be 125 to 8 Square it human. Oh, they gave me the area so to get now if they give me the area or the volume I always want to find the linear first So to get the linear it's going to square root square root. It's going to be four to five and Now I can find the volume because it's going to be cubed cube. It's going to be 64 To 125 Here they gave me the volume. I'm going to find the linear first. Oh now here. I square rooted What do I do if they give me the volume? I don't square root Cube root. Now you better know what that is on your calculator or between now and Monday You better figure it out. I will not help you find that button on Monday cube root Which is five? squared 25 Cube root which is five to four cube root of 125 cube root of 64 which becomes 25 to 16 cube root which is seven to four which becomes 49 to 16 a half mark for each square because it's out of six and there's six lines and there's two squares in each Line there's 12 squares all together What's that you say Tatiana? Yes, absolutely if you got perfect give me stuff like this To make your county easier why give yourself a score out of 20 on this page and let's keep going turn the page Okay Says complete the following table. All right Original surface area 120 now the linear scale factor is two to one That means that the area scale factor is four to one and the volume scale factor is eight to one I went squared. I went cubed so to find the new area. I'm gonna multiply by four To find the new volume. I'm gonna multiply the original volume by eight. Is that right? 480 and 1600 Half mark half mark The linear scale factor they gave me here was one to four So the area is one to sixteen and the volume is one to sixty four So to find the new area I'm gonna go a hundred and twenty times one divided by sixteen divided by because it's one to sixteen not sixteen to one And in fact Nikki, I could have skipped the times by one part But I'll put it in there so that I use the whole one to sixteen cut your media on your wake now though Good gosh, I don't call you Nikki twice Alyssa That's Nikki. Did you sit there last time? That's why I'm looking there and okay. I'm sorry, Alyssa I apologize deeply Nikki. Hi there Nikki there. Hi Alyssa. I'm sorry. I Humbly apologize. You get a candy later on Let's try that again. Alyssa Alyssa Alyssa my child joy of my heart light of my life apple of my eye Square it right cubit and because it's a reduction 120 times 1 divided by 16 my new surface area 7.5 folks is that right and 400 times 1 divided by 64 6.25 there's my new volume Now they're gonna ask me to figure out the various Scale factors they told me the new area and the old area. I can find the area factor by going new divided by old new divided by Old the area scale factor this one here is nine What's my linear scale factor then? Because this is my area square. Yeah, what's my linear three? What's my volume? 27 so now I'm gonna go 50 Sorry, I don't need to go 50 times 9 to get 450, but I can go 100 times 27 to get 2,700 and the linear scale factor is three By the way, I'm looking the people that were last day are looking kind of dazed watch the video if you haven't already And if you haven't already just shut up Let's see They gave me the new volume and the original volume so my volume scale factor is 64 How can I figure out my linear scale factor? Cube root the linear scale factor is 4 and now that I know my linear scale factor my area scale factor gonna be 16 So I'm gonna multiply the 80 by 16 80 times 16 Is your area 1280? And let's erase that so the answer here would be 4 the answer here would be 1280 5 to 2 that's gonna be the same as 25 to 4 or 125 over 8 for my area and for my volume so 60 Times 25 divided by 4. There's my new area 375 and 80 times 125 divided by 8. There's 1250. There's my new volume 3 to 2 is my linear that means 9 to 4 is my area that means that cube cube 27 to 8 is my volume so 80 Times 9 divided by 4. There's my new area 120 times 27 divided by 8. There's my new volume 405. Is that right folks? So give yourself a score out of 6 there half mark for each square. I'm gonna do that just so it's not so cluttered nearly done an Object has an original surface area of 48 and a volume of 120 If the linear scale factor of 5 to 2 is applied, what's the surface area sale scale factor? Well, it's 5 to 2 Squared it's 25 to 4 What's the volume scale factor? 5 to 2 cubed It's 125 Over 8 What's the new surface area original surface area times area scale factor? 400 no 300 what's the new volume original volume times? volume scale factor 120 times 125 divided by 8 1875 One mark one mark one mark one mark Give yourself a little score out of 10 here and The last question below is a 1 centimeter to 15 meters scale model of the Statue of Liberty Based on the scale model. What's the actual height? So I'm gonna use this is my conversion factor 1 centimeter To 15 meters Equals when you measured with the ruler from here to here What did you get? 4.6 4.7. Yeah, have I got to the answer yet? patience So if you use 4.6, I'm gonna give you a range of answer. I'm gonna be a range of answer. That's why I hang on That's the centimeters and x in meters. There's your real height Tanner, how will I solve this equation? Did I mention lately the cross mode? Okay I'm sorry, but it really is one of the most useful things you'll learn x is gonna be 15 times 4.6 X is gonna be 15 times 4.6 69 I'll take 69 meters if you said 70 meters. I'd take that. What did you use 4.7? I'd take 70.5 4.5 which probably was what I was trying to make it because I probably would have tried to make it close to a nice number It's actually 67.5. So I'll take 70.5. I'll take 67.5 Alyssa whose name I remembered this time. What was your question or did I answer it already? What did you round it off to? sorry Five centimeters. That's a that's a big chunk You never round off before you do the count it just a rule of thumb for math or physics never round off before you do a Calculation round off afterwards and if it's big you got you a calculator Okay, so I'm gonna say it's out of two. I'm gonna take a half mark off for that So you would have got 75 yeah, I would take that as well 71. I would take 68 as well In fact, I would say thank you for reading the instructions any other questions so Here's how it works those five of you that were away. You're gonna put a great big Omit at the top. Otherwise, I'm giving you a zero The rest of you add up your score out of 36 and write it right there then Divide your score by two to give yourself a score out of 18. Okay