Explanation for Question 16 From the Math (Calc) Section on the 2020 March Sat
So number 16 has given us a lot of data about the different side 2 lengths in this shape. It tells us that a B is equal to Ady 3 and I'll denote that using a congruency dash right here, 4 and that BC is equal to CD, 5 which I'll show with these dashes. And then also B E is equal to 6 two. So this line is two right here. 7 Um, BC is equal to four and a C. 8 So this whole line down the middle right here is equal to 10. 9 And what we're doing is trying to find the area of the triangle that 10 I've highlighted in blue. Right? 11 And so the first thing that we need to do to find the area 12 of this triangle, which I'll redraw right here, 13 it's figuring out what our height is, which is going to be that dash 14 line and what our bases, because when we know the base and the height, 15 we can multiply them, divide them by two and get our area. 16 And so perhaps the easiest part of this whole thing is going to be 17 the height. I mean, the base, the height is the one that takes a 18 little bit of work, but with the base, we see that half of the 19 basis too. So the other half must also be two. 20 And then we have a base length of four. Now you may have been 21 hesitant to simply know that half of it was to you. 22 Might've thought, oh, I'm not sure if it's two or not. 23 The reason that we know it's exactly half is because what they've drawn here 24 for us is eight kite. They'd given us all the requirements for a kite 25 by telling us that these two sides working grit and these two s...