Question

Find the area of the circle of radius $7$cm (use $\pi = \dfrac{{22}}{7}$ )

Answer 1

Hint: To find the area of circle, we will use the formula which gives relation between the area of the circle and the radius of the circle and is given as-
$ \Rightarrow $The area of the circle=$\pi {r^2}$where r is radius of the circle and $\pi $ is pi constant. Put the values of radius r and pi constant in the formula and solve it to get the answer.

Complete step-by-step answer:
Given, the radius of the circle=$7$cm and $\pi = \dfrac{{22}}{7}$
We have to find the area of the circle.
Let AB be the radius of the circle in the given diagram-

We will use the formula of the area of the circle which is given as-
$ \Rightarrow $The area of the circle=$\pi {r^2}$where r is radius of the circle and $\pi $ is pi constant.
On putting the value of radius and pi constant in the formula, we get-
$ \Rightarrow $The area of the circle=$\dfrac{{22}}{7} \times {\left( 7 \right)^2}$
We can write ${a^2}$ as $a \times a$ because the square of a number is a multiple of itself. So get-
$ \Rightarrow $The area of the circle=$\dfrac{{22}}{7} \times 7 \times 7$
On solving, we get-
$ \Rightarrow $The area of the circle=$22 \times 7$
On multiplication, we get-
$ \Rightarrow $The area of the circle=$154{\text{ c}}{{\text{m}}^2}$
The area of the circle of radius $7$cm is $154{\text{ c}}{{\text{m}}^2}$.

Note: Here, the students need to remember to put the unit of the area of the circle in the answer because the answer will be considered incomplete without the unit of the area. Also, remember that the area is always a squared unit like ${{\text{m}}^2}$ or ${\text{c}}{{\text{m}}^2}$. The formula of area of the circle is used to measure space occupied by a circular object or field like area of a circular table or area of a circular plot.