Question

solve for a.
a
20
7
4
o 21
o 35
o 14
o 28

Explanation:

Step1: Use similar - triangle property

Since the two triangles are similar, the ratios of their corresponding sides are equal. That is, $\frac{4}{20}=\frac{7}{A}$.

Step2: Cross - multiply

Cross - multiplying the proportion $\frac{4}{20}=\frac{7}{A}$ gives $4A = 20\times7$.

Step3: Solve for A

First, calculate $20\times7 = 140$. Then, $A=\frac{140}{4}=35$.

Answer:

35