Question

10 8 14 4 7 ?

Explanation:

Step1: Assume similar - triangle relationship

If the two triangles are similar, the ratios of corresponding sides are equal. Let the unknown side be $x$.
We assume $\frac{10}{x}=\frac{8}{4}=\frac{14}{7}$ since for similar triangles, the ratios of corresponding sides are the same.

Step2: Solve for $x$ using the ratio $\frac{8}{4}$

From $\frac{10}{x}=\frac{8}{4}$, cross - multiply gives $8x = 10\times4$.
Then $8x=40$, and $x=\frac{40}{8}=5$.

Answer:

5