The area of the circle whose radius is 21 meter.

The correct answer is Option (2) → 1386 m²

The area of a circle of radius \(r\) is \(\pi r^{2}\). The radius 21 is a multiple of 7, so taking \(\pi=\frac{22}{7}\) cancels the 7 and gives a whole number. The radius is in metres, so the area comes out in square metres.

• Square of the radius: \(r^{2}=21\times21=441\)

• Area of the circle \(\displaystyle =\frac{22}{7}\times441=22\times63=\) 1386 m²