Question

The radius of the circle is 7 cm and finds its circumference and area.

Answer 1

Hint: We will put the value of radius r=7cm in the formula of area of circle that is $\pi {r^2}$ and the circumference in the very same way $\pi d$ . And here d is diameter which is equal to 2r.
The area of circle having radius ‘r’ is $\pi {r^2}$ and circumference of circle with diameter ‘d’ is $\pi d$

Complete step-by-step answer:
So here we are given a circle with radius 7cm.
Area of a circle is given by the formula $\pi {r^2}$
So, we will find the area by putting radius as the given value that is 7cm.
So
$\Rightarrow \pi {r^2} = \pi \times {7^2} = \dfrac{{22}}{7} \times 7 \times 7 = 22 \times 7 = 154$ sq. cm
Now we will find the circumference of the circle. So, the enclosing boundary of a curved geometric figure, especially a circle is known as circumference. We have the formula of the circumference of the circle which is given by $\pi d$ .
Here d is the diameter of the circle.
Diameter is the line segment that is passing from one end of the circle to another end of the circle through the center of the circle.
So basically, diameter is twice the length of the radius. Hence, we have d=2r
Now we will calculate the circumference of circle with the given radius that is 7cm
So, let’s calculate the circumference
$\Rightarrow \pi d = \pi \times (2 \times 7) = \dfrac{{22}}{7} \times 14 = 44$ cm
Hence, the area of the given circle with radius 7 is given by 154 sq. cm and the circumference is given by 44 cm respectively.
So, the correct answer is “the area of the given circle with radius 7 is given by 154 sq. cm and the circumference is given by 44 cm respectively.”.

Note: We can calculate the circumference from the area of the circle also that is by multiplying the area by 2 and then dividing it by the radius. This is a simple technique that can also be derived by using the formula of circumference and area of a circle.