Question

A 29 ft long rope is tied to the top of a flag pole. The rope is staked to the ground 21 ft away from the base of the pole. How tall is the flag pole? A) 20 ft B) 28 ft C) 32 ft D) 36 ft

Answer 1

Answer: option A is the correct answer.

Explanation:

The rope, the flagpole and the ground would form a right angle triangle. The length of the rope represents the hypotenuse of the right angle triangle. The vertical height of the flagpole represents the opposite side of the right angle triangle. The distance from the point where the rope is staked to the ground to the base of the pole represents the adjacent side of the right angle triangle.

To determine the height if the flagpole h, we would apply Pythagoras theorem which is expressed as

Hypotenuse² = opposite side² + adjacent side²

Therefore,

29² = 21² + h²

841 = 441 + h²

h² = 841 - 441 = 400

h = √400 = 20 ft