147۰994907 ÷ 2 =73۰99745385. 148۰0140971 ÷ 2 =74۰00704854. The radius of the circle is 74 cm to the nearest cm. Practise pi and working out the circumference of circles with this quiz.

The circumference of a circle = \(\pi d\) or \(2\pi r\). Look at the sector of the circle shown below. To calculate the length of the arc, we need to know what fraction of the circle is shown.