Question

A rectangular piece is 20 m long and 15 m wide. From its four corners, quadrants of radius 3.5 m have been cut. Find the area of the remaining part.

Answer 1

Area of the quadrant of one circle = $\frac{1}{4}\times \pi r^2$
$$\begin{gathered} =\frac{1}{4}\times \frac{22}{7}\times 3.5\times 3.5 \\ =9.625{\mathrm{m}}^2 \end{gathered}$$

Area of the quadrants of four circles = $4\times 9.625=38.5$ cm²
Area of the rectangle = $15\times 20=300{\mathrm{m}}^2$

∴ Area of the remaining part = Area of the rectangle $-$ Area of the quadrants of four circles
= 300 $-$ 38.5
= 261.5 ${\mathrm{m}}^2$