WAEC - Mathematics (2016 - No. 33)
A sphere of radius rcm has the same volume as cylinder of radius 3cm and height 4cm. Find the value of r
\(\frac{2}{3}\)
2
3
6
설명
Volume of sphere = Volume of cylinder
i.e. \(\frac{4}{3} \pi r^3 = \pi r^2 h\)
\(\frac{4}{3} \pi r^3 = \pi \times 3^2 \times 4\)
r3 = \(\frac{\pi \times 9 \times 4 \times 3}{4 \pi}\)
r = 3\(\sqrt{27}\)
= 3
i.e. \(\frac{4}{3} \pi r^3 = \pi r^2 h\)
\(\frac{4}{3} \pi r^3 = \pi \times 3^2 \times 4\)
r3 = \(\frac{\pi \times 9 \times 4 \times 3}{4 \pi}\)
r = 3\(\sqrt{27}\)
= 3