Explanation for Question 18 From the Math (No Calc) Section on the Official Sat Practice Test 6
18 gives us this diagram, this picture of these triangles. 2 And it says in the figure above BD is parallel to a E. 3 So BD is parallel to a E what is the length 4 of CE? So CE is this line right here now 5 because they're nested triangles, triangle CBD is 6 inside of triangle CEA. 7 We know that this angle is going to be the same for both. 8 And then we also know that this angle is the same for both because 9 these lines are parallel. So they both form a right angle with the bottom 10 based off of that, we know that they're similar triangles and this is true 11 of most many NetSuite triangles. 12 That means that all of their angles are the same, 13 um, within both triangles. 14 So this single is the same. And then this angle is the same measurement 15 as this angle. Now it doesn't mean that the size links are the same, 16 and that should hopefully be true, but that should hopefully be obvious from looking 17 at the picture. 18 Um, but it does mean that they have a ratio relating the 19 two of them. So we know that, 20 let me erase this so you can see it a little better. 21 We know that BD line BD is equal to six and line AEG 22 is equal to 18. So that ratio right there 23 of D B over a E is 24 going to be equal to six over 18, 25 which is one third. And from that, 26 we know that the scale-up factor from triangle CBD to triangle CAE is 27 going to be multiplying by three. So in the same way that this side 28 was multiplied by three, to get to 18, this side, 29 CB to get to C...