You are on a jungle expedition and come to a raging river. You need to build a bridge across the river. You spot a tall tree directly across from you on the opposite bank (point A ). You place a pole in the ground to mark the position directly across from the tree. From the spot you are standing, you walk directly downstream 16 feet and place another pole (point C ). You keep walking down stream and mark a third spot with a pole that is 7 feet from your last pole (point D ). Turning perpendicular from the last pole, you walk away from the river 9 feet to another position and place a fourth pole (point E ). a. Determine if the two triangles are similar. Explain which similarity theorem you used and why. b. Use proportions to calculate the distance across the river. A large tree is close to point C and we could chop it down at an angle to reach point A and safely cross the river. c. How tall does the tree need to be to span the river from point C to A ?