Answer:
9.628 cm²
Step-by-step explanation:
Let A be the area of the sector OAB
Let a be the area of the sector OCD
The shaded area = A − a
[tex]\begin{aligned}A &=\frac{1}{12} (\pi \times 7^{2}) \\&=12.828 \ldots\end{aligned}[/tex]
[tex]\begin{aligned}a & = \frac{1}{12}\left(\pi \times 3.5^{2}\right) \\&=3.2 \ldots\end{aligned}[/tex]
The shaded area ≈ 12.828 - 3.2 ≈ 9.628 cm²
