Question

Find the diameter and the circumference of the circle if its area is $6.16m^2.$

Answer 1

Step 1 Finding the diameter of the circle:

Given the area of the circle is $6.16m^2.$

Area of the circle$=$ ${\mathrm{\pi r}}^2\mathrm{sq}.\mathrm{units}$ [ Where $\text{'}r\text{'}$ is the radius of cirlce]

Therefore,

$$\begin{gathered} \frac{22}{7}\times r^2=6.16 \\ \Rightarrow r^2=6.16\times \frac{7}{22} \\ \Rightarrow r^2=1.96m \\ \Rightarrow r=1.4m \end{gathered}$$

We know that, diameter$\left(d\right)=2\times r$

$\begin{array}{rcl}& \Rightarrow & d=2\times 1.4m\\ & =& 2.8m\end{array}$

Hence, the diameter of the circle is $2.8m.$

Step 2 Finding the circumference of the circle:

Circumference of the circle is $2\mathrm{\pi r}$ [ Where $\text{'}r\text{'}$ is the radius of cirlce]

$$\begin{gathered} =2\times \frac{22}{7}\times 1.4 \\ =2\times 22\times 0.2 \\ =8.8cm. \end{gathered}$$

Hence, the circumference of the circle is $8.8cm$