Question

Find the circumference of a circle whose diameter is $10.5cm$

Answer 1

Hint: A circle is a close two-dimensional figure in which the set of all the points in the plane is equidistant from a given point called “center”. It is a round shaped figure. Every circle has radius and it is denoted by ‘r’.
As we know that perimeter of circle
$ \Rightarrow P = 2\pi R$
Here,
P=Perimeter of circle
R=radius of circle.

Complete step-by-step solution:
Given,
Diameter of circle, $D = 10.5cm$
As we know that radius is half of diameter, $R = \dfrac{D}{2}$
So the radius of center circle, $R = \dfrac{{10.5}}{2}cm$
As we know that
$ \Rightarrow P = 2\pi R$
Put the values in equation
$ \Rightarrow P = 2 \times \pi \times \dfrac{{10.5}}{2}$
$\therefore \pi = \dfrac{{22}}{7}$
Simplify the equation
$ \Rightarrow P = 2 \times \dfrac{{22}}{7} \times 10.5$
$ \Rightarrow P = 22 \times 3$
$ \Rightarrow P = 66cm$
The perimeter of the circle is $66cm$.

Note: The coordinate axis divides the circle into the four parts known as quadrants. Labelled them as first, second, third and fourth. The perimeter of the circle is the length of the circle. When we make a circle from rectangular or square the area of the rectangle or square is equal to the perimeter of the square.