Its C. 15 x ? = 405 The question is kind of like writing a fact family. You need to find the same unknown number that belongs in the question mark in the rest of them. So since 405 ÷ 15 = 27, C. 15 x 27 = 405 ? = 27 (It also needs to make sense :P)
the exterior angle of a triangle is equal to the sum of the opposite interior angles. Therefore, in the tall triangle, 60 + 40 = 100, meaning the bottom left angle in the small triangle is 100-64=36. And b/c angle sum of a triangle is 180°, 180-36-56=88°
