WAEC - Mathematics (2000 - No. 45)
The area of a circle is 38.5cm2. Find its diameter [take \(\pi = \frac{22}{7}\)]
22cm
14cm
7cm
6cm
설명
\(\pi r^2\) = 38.5
\(\frac{22}{7} r^2\) = 38.5
r\(^2\) = \(\frac{38.5 \times 7}{22}\)
r = \(\sqrt{12.25}\) = 3.5
diameter = 2r = 2 x 3.5 = 7cm
\(\frac{22}{7} r^2\) = 38.5
r\(^2\) = \(\frac{38.5 \times 7}{22}\)
r = \(\sqrt{12.25}\) = 3.5
diameter = 2r = 2 x 3.5 = 7cm