Question

find the length x.

Explanation:

Step1: Use similar - triangle property

Since the two right - angled triangles are similar, the ratios of their corresponding sides are equal. That is, $\frac{4}{3.5}=\frac{8}{x}$.

Step2: Cross - multiply

Cross - multiplying the proportion $\frac{4}{3.5}=\frac{8}{x}$ gives $4x = 8\times3.5$.

Step3: Solve for x

First, calculate $8\times3.5 = 28$. Then, $x=\frac{28}{4}=7$.

Answer:

7