Two adjacent angles whose exterior sides are opposite rays are complementary.
always
sometimes
never

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?

Me because i don't understand how to do it.: )

Will mark kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown (a) can kayla conclude that δabc and δedc are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?