Charmaine constructs a triangle with angles measuring 65° and 38°. What must be true of the measure of the third angle in her construction? a) It must measure exactly 77°.
b) It must measure exactly 87°.
c) It can have any measures less than 103°.
d) It can have any measure greater than 27°.

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?