Help me pls! I don't understand my math omg

Complete each statement from the information given and the triangle criterion you used. if the triangles cannot be shown to be congruent, leave the box for the second triangle blank and choose for reason “cannot be determined.” carbon - regular hexagon. ∆can ≅ ∆ by

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?

How would you find the height of points on the circle? the topic is trigonometry.