Question

x ft 15 ft 5 ft 3 ft 12 6

Explanation:

Step1: Identify similar triangles

The two right - angled triangles are similar because their corresponding angles are equal.

Step2: Set up proportion

For similar triangles, the ratios of corresponding sides are equal. So, $\frac{3}{15}=\frac{5}{x}$.

Step3: Cross - multiply

Cross - multiplying gives $3x = 15\times5$.

Step4: Solve for x

$3x=75$, then $x=\frac{75}{3}=25$.

Answer:

$25$ ft