 This video is called Right Triangle Trig 4. So it's two more problems, just like the ones we worked on, where the focus is to really look at the picture, make sure you set up your equation correctly, know the process to solve it, and then hopefully you can get your calculator to get the same answer as me. But again, if that's the part that's giving you trouble, do everything else but the actual calculation and get help from your teacher soon. So looking at this one, we're going to go from the perspective of 70 degrees where the 20 would be the adjacent, the x would be the opposite, because then the one that doesn't have any information is the hypotenuse. So we're going to use, the hypotenuse won't help us. We're going to use opposite and adjacent, which hopefully you can recognize using Sokotoa that it is a tangent. So we have the setup is the tangent of 70 degrees equals the opposite, which is x over the adjacent, which is 20. Now on a tester quiz, hopefully you can write a 70 a little bit neater than I can. But on a tester quiz, that setup right there by doing this amount of work would actually get you some partial credit on the test because a lot of stuff has happened. You're showing us that you can recognize opposite and adjacent, that you can recognize it's a tangent and that you can set up the equation correctly. So getting this far is important. Notice you were able to do all of that without a calculator. The next step is important too to get the x alone. It's just like solving an algebra problem. So the first thing we're going to do is get rid of our denominator. So you take whatever is in the denominator. In this case, it's 20. Multiply both sides by 20. So on the right-hand side, they cancel. You're left with a plain old x. So on the left-hand side, here's where your calculator, knowing how to use your calculator will come in handy. You're going to do tangent of 70 press equal times 20 and press equal. And you should get an answer that rounds to 54.9. Try it. See if you can play with your calculator with the order you punch things in, with how much you press equal, things like that. And see if you can get the same answer. And like I said, if you're having trouble with that, getting to 54.9, just get some help. All right, problem 19. We're getting closer. This one, again, a right triangle. We're never going to go from the perspective of the 90-degree angle. So I'm going to go from the perspective of the 40. That makes 25 my opposite and x my adjacent. Looking at Sokotoa, you can see that opposite and adjacent is a tangent. So let's set up our problem. It will be the tangent of 40 equals the opposite, which is 25 over the adjacent, which is x. So looking here, by setting it up correctly using the 40, the 25 over the x, recognizing it was a tangent problem, you've earned some, you know, partial credit on a test. You'll earn full credit by solving. Now maybe by this time you've noticed that something's a little different about this problem than the others we've worked on. And if you notice that the x was in the denominator, you're right. So far, all the problems we've worked on, the x is in the numerator. Don't let that throw you off. We're going to solve it the exact same way. To get the x alone, when you have a fraction, let's get rid of the fraction. So you take whatever's in the denominator, this time it's the x, multiply both sides by x. So the x is on the right, cancel, and you're left with only 25, and all of a sudden, my x is on the left side of my equation. I still want to get the x alone, so I'm going to have to this time move the tangent of 40. Well, ask yourself, what is the tangent of 40 doing to the x? It's multiplying it. So to get rid of it, we're going to do the inverse and divide both sides by the tangent of 40. So on the left-hand side, the tangents of 40 cancel, and now you have a new skill to learn on your calculator. You have to do 25 divide by the tangent of 40. You will end up getting 29.8. So please, I beg of you, to pause the video for just a minute and play around with your calculator and see if you can figure out how your calculator works to get 29.8, because they truly are all a little bit different. Some pieces of advice, do 25 divide by tangent of 40, press equal. Some calculators, you have to do 40 and then hit tangent. Lots of different things to try. So play around with it and see if you can get 29.8.