Question

In triangle JKL, angles J and L each measure 51° and JK = 18. Triangle PQR is similar to triangle JKL, where J corresponds to P, K corresponds to Q, and QR = 36. Which expression represents the length of segment PR?

Answer 1

Explanation:

Triangle JKL is a 51-51-78 triangle, since the angles in a triangle must add up to 180°. Since triangle PQR is similar to triangle JKL, it must also be a 51-51-78 triangle. Since corresponding sides in similar figures are in proportion, we can set up a proportion to find the length of PR:

(PR)/(JK) = (PQ)/(JL) = (36)/(18)

Cross multiplying and solving for PR, we find:

PR = (JK) * (PQ)/(JL) = 18 * 36/18 = 36