WAEC - Mathematics (2019 - No. 21)
The total surface area of a solid cylinder 165cm\(^2\). Of the base diameter is 7cm, calculate its height. [Take \(\pi = \frac{22}{7}\)]
7.5 cm
4.5 cm
4.0 cm
2.0 cm
Spiegazione
165 = 2 x \(\frac{22}{7}\) x \(\frac{7}{2}\) x h + 2 x \(\frac{22}{7}\) x \(\frac{7}{2}\) x \(\frac{7}{2}\)
165 = 22h + 77
\(\frac{22h}{22} = \frac{88}{22}\)
height = 4cm