Question

Circumference $\mathrm{C}$ of a circle can be found by multiplying diameter $\mathrm{d}$ with ___.

Answer 1

Circumference:

The circumference of a circle is the perimeter of the circle. It is the total length of the boundary of the circle.

Understand that for a circle whose radius $\left(r\right)$ and diameter $\left(d\right)$are related as:

$$\begin{gathered} \mathrm{Diameter}\left(\mathrm{d}\right)=2\times \mathrm{radius}\left(\mathrm{r}\right) \\ \therefore \mathrm{d}=2\mathrm{r} \end{gathered}$$

Circumference $\mathrm{C}$ of a circle having radius $r$ is given as $2\pi r$.

Therefore,

$\begin{array}{l}\mathrm{C}=2\mathrm{\pi r}\\ \Rightarrow \mathrm{C}=\mathrm{\pi d}\end{array}\begin{array}{l}\left[\because d=2r\right]\\ \end{array}$

Hence,circumference $\mathrm{C}$ of a circle can be found by multiplying diameter $\mathrm{d}$ with $\pi$.