Explanation for Question 6 From the Math (No Calc) Section on the 2019 March Sat
Question six says triangle, 2 ABC and triangle D E F are similar triangles were lines, 3 a, B and D E are corresponding sides. 4 If D equals two AB and the perimeter of triangle, 5 ABC is 20. What is the perimeter of triangle? 6 D E so all that you need to know here are that 7 these two triangles are similar. That D E is equal to two 8 AB and those sides are corresponding. 9 So whenever triangles are similar, 10 the ratio of two corresponding sides should be the same as the ratio 11 of two other corresponding sides. And not only that, 12 but it should be the same ratio of one, 13 one perimeter to the other's perimeter. 14 So D E and AB are corresponding sides. 15 I'm just going to draw these triangles out to depict this. 16 So a, B, C, 17 and D E D E F 18 a B is, or D is equal to two a B, 19 which means the ratio of these triangles is one to two. 20 So that means that the ratio of their perimeters should be the same. 21 So for trying to find the ratio of the perimeter, 22 I'm sorry if we're trying to find the perimeter of Def, 23 and we know that the perimeter of triangle ABC 24 is 20. All we have to do is multiply it by two, 25 and we'll find that X is equal to 40. 26 And therefore the answer is.