You can use pi to calculate the circumference and area of a circle. Pi is represented by the symbol π and is a number which is approximately 3.141592.

What is a commonly used value of \(\pi\)?

\[{3.14}\]

\[{3.16}\]

\[{13.5}\]

Which of the following is not a formula to find the circumference of a circle?

\[\pi{r}^{2}\]

\[\pi{d}\]

\[{2}\pi{r}\]

What is the formula to find the area of a circle?

What is the circumference of a circle that has a diameter of \({7}~{cm}\)?

\[{20.9}~{cm}~(to~1~dp)\]

\[{22.0}~{cm}~(to~1~dp)\]

\[{24.6}~{cm}~(to~1~dp)\]

What is the circumference of a circle that has a radius of \({5}~{cm}\)?

\[{15.7}~{cm}~(to~1~dp)\]

\[{25.8}~{cm}~(to~1~dp)\]

\[{31.4}~{cm}~(to~1~dp)\]

What is the diameter of a circle that has a circumference of \({15}~{cm}\)?

\[{4.6}~{cm}~(to~1~dp)\]

\[{4.7}~{cm}~(to~1~dp)\]

\[{4.8}~{cm}~(to~1~dp)\]

What is the area of a circle that has a radius of \({5}~{cm}\)?

\[{78.5}~{cm}^{2}~(to~1~dp)\]

\[{79.0}~{cm}^{2}~(to~1~dp)\]

\[{79.5}~{cm}^{2}~(to~1~dp)\]

What is the area of a circle that has a diameter of \({16}~{cm}\)?

\[{200.0}~{cm}^{2}~(to~1~dp)\]

\[{201.1}~{cm}^{2}~(to~1~dp)\]

\[{804.2}~{cm}^{2}~(to~1~dp)\]

What is the area of a half circle that has a radius of \({10}~{cm}\)?

\[{157.1}~{cm}^{2}~(to~1~dp)\]

\[{314.2}~{cm}^{2}~(to~1~dp)\]

\[{412.5}~{cm}^{2}~(to~1~dp)\]

What is the radius of a circle that has an area of \({42}~{cm}^{2}\)?

\[{3.5}~{cm}~(to~1~dp)\]

\[{3.6}~{cm}~(to~1~dp)\]

\[{3.7}~{cm}~(to~1~dp)\]