Question

What is the circumference of a circle when the diameter is 18?

Answer 1

Determining the circumference of a circle when the diameter is $18$.

Diameter = 18

Using the formula of diameter to calculate the radius.

$$\begin{gathered} \Rightarrow Diameter=2\times radius \\ \Rightarrow radius=\frac{Diameter}{2}(\because Diameter=18) \\ \Rightarrow =\frac{18}{2} \\ \Rightarrow =9 \end{gathered}$$

Now calculate the circle circumference by using the formula.

$$\begin{gathered} C=2\mathrm{\pi }\mathrm{r} \\ \Rightarrow =2\times \frac{22}{7}\times 9 \\ \Rightarrow =56.5714 \end{gathered}$$

Hence, the circumference of a circle $56.5714$ when the diameter is $18$.