 Hello and welcome to another problem-solving session on triangles the question here says that qa and pb are perpendicular to a b Okay, so perpendicular means this is perpendicular right and a o is 10 centimeter so this length here is 10 Okay, and bo is 6 Right, this is given and pb is 9 is 9 centimeter and What we need to find out is we are need to find out the length of aq. Okay, so how to go about it? Clearly, you know, there are two triangles visible in this figure and they appear to be similar as well So hence I will write in triangle a o q and Triangle Bo p bo p right angle a is Equal to angle b both are 90 degrees Because q and pb are pb are perpendicular to a b and Angle a o q Is equal to angle to b or bo p and This is because of vertically opposite angles So I'm just writing in short vertically opposite angles. Therefore by a a similarity criterion similarity Criterion what do we get? We get a o By ob Will be equal to aq by pq Is it the sides will be proportional corresponding sides will be proportional from here I can find out the value of a aq. So aq is equal to a o by ob Into pq A o is 10 Ob is 6 and pq is 9 Is it so this is the answer? So if I simplify this I get 15 centimeter as the answer So isn't it a very good technique of finding out? Dimensions of geometrical figures, especially when you're doing construction architecture or even trying to find out height of buildings similarity concepts of similarity and similar triangles are Going to be very very useful. Okay, so let's understand this more in a practical example