Question

In △PQR, what is the length of QR

Answer 1

A

Answer 2

B

Answer 3

C

Answer 4

D) 28

Answer 5

cos(45) = QR/56
QR = 56cos(45)
QR = 39.5 , which isnt one of the answer choices ?

Answer 6

since the triangle is isosceles let 1 side be x. Then both shorter sides are x

using Pythagoras Theorem

x^2 + x^2 = 56^2

2x^2 = 3136

x^2 = 1568

\[x = \sqrt{1568} = 28\sqrt{2}\]