Question

Find the area of a circle when radius $=5cm$ .

Answer 1

Hint: In the question we are asked to find the area of a circle with given radius. For this we must know the formula of circle i.e. $A=\pi {{r}^{2}}$ . The formula is simple and only needs the radius of the circle to find its area.

Complete step-by-step answer:

Here, to find the area of the circle, we must know the formula of the circle. The formula to find the area of a circle is $A=\pi {{r}^{2}}$ .
Where, A is the area of the circle,
$\pi $ is the constant ratio of circumference of a circle,
‘r’ is the variable representing the radius of the circle which is the distance from the centre outward.
From the question, we know that –
$r=5cm$
Here, we will substitute the value of radius in the formula of area of the square.
$\begin{align}
  & A=\pi {{r}^{2}} \\
 & A=\dfrac{22}{7}\times {{\left( 5 \right)}^{2}}\text{ }\left( \because \pi =\dfrac{22}{7} \right) \\
 & A=\dfrac{22}{7}\times \left( 5\times 5 \right) \\
 & A=\dfrac{22}{7}\times \left( 25 \right) \\
 & A=\dfrac{550}{7} \\
 & A=78.57c{{m}^{2}} \\
\end{align}$
Hence, the area of the circle with the radius 5cm is \[78.57c{{m}^{2}}\]

Note: Area of a circle is the region occupied by the circle in a two dimensional plane. It can be determined easily using a formula, $A=\pi {{r}^{2}}$. In the solution, we can also use the value of $\pi $ as 3.14. This area formula is useful for measuring the space occupied by a circular field or a plot. Suppose, if you have the plot to fence it, then the area formula will help you to check how much fencing is required.