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The curved surface area of a cylindrical pillar is 264 m2 and its volume is 924 m3 $$\left( {{\text{Taking }}\pi = \frac{{22}}{7}} \right).$$ Find the ratio of its diameter to its height
Answer & Solution
Correct Answer:
Option
D
$$\eqalign{
& 2\pi rh = 264{\text{ }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}\left( {\text{i}} \right) \cr
& \pi {r^2}h = 924{\text{ }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}{\text{. }}\left( {{\text{ii}}} \right) \cr
& {\text{On dividing}}:\frac{{2\pi rh}}{{\pi {r^2}h}} = \frac{{264}}{{924}} \cr
& \frac{2}{r} = \frac{{264}}{{924}} \cr
& r = \frac{{924 \times 2}}{{264}} \cr
& r = 7{\text{ cm}} \cr
& {\text{Diameter}} = 2r = 2 \times 7 = 14{\text{ cm}} \cr
& {\text{Putting, }}r = 7{\text{ in equation }}\left( {\text{i}} \right) \cr
& 2\pi rh = 264 \cr
& h = \frac{{264 \times 7}}{{2 \times 22 \times 7}} \cr
& h = 6{\text{ cm}} \cr
& {\text{Required ratio}} = \frac{{2r}}{h} = \frac{{14}}{6} = \frac{7}{3} \cr} $$
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