Question

a flagpole casts a shadow of 15 feet. at the same time, a 5 - foot tall person standing nearby casts a shadow of 3 feet. what is the height of the flagpole?

Explanation:

Step1: Set up proportion

Since the ratio of height to shadow - length is the same for both the person and the flagpole, we can set up the proportion $\frac{h}{15}=\frac{5}{3}$, where $h$ is the height of the flagpole.

Step2: Cross - multiply

Cross - multiplying gives us $3h = 5\times15$.

Step3: Calculate the right - hand side

$5\times15=75$, so the equation becomes $3h = 75$.

Step4: Solve for $h$

Dividing both sides of the equation $3h = 75$ by 3, we get $h=\frac{75}{3}=25$.

Answer:

25