Question

amanda wanted to measure the height of her schools flagpole. she placed a mirror on the ground 48 ft from the flagpole, then walked backwards until she was able to see the top of the pole in the mirror. her eyes were 5 ft above the ground and she was 12 ft from the mirror. find the height of the flagpole to the nearest tenth of a foot.

Explanation:

Step1: Set up proportion

Since the angles of incidence and reflection are equal, the two right - angled triangles formed are similar. Let $h$ be the height of the flagpole. The proportion is $\frac{h}{48}=\frac{5}{12}$.

Step2: Solve for $h$

Cross - multiply: $12h = 48\times5$. Then $12h=240$. Divide both sides by 12: $h=\frac{240}{12}=20$.

Answer:

20.0 ft