4. You stand on one side of the creek and your friend stands directly across the creek from you on the other side as shown in the figure.

Your friend is standing 5 feet from the creek and you are standing 5 feet from the creek. You and your
friend walk away from each other in opposite parallel directions. Your friend walks 50 feet and you walk
12 feet.
a. How do you know that the triangles formed by the lines are similar?
b. Calculate the distance from your friend's starting point to your side of the creek. Round your
answer to the nearest tenth if necessary.
c. What is the width of the creek? Justify your reasoning?