In the diagram, . Triangles P M N and Q S R are shown. The lengths of sides P N and R Q are congruent, the lengths of sides Q S and P M are congruent, and the lengths of sides M N and R S are congruent. If QR = 20 in., RS = 7 in., and SQ = 24 in., what is PN? 3 in. 7 in. 20 in. 24 in.

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?