The ratio of the volume of first and second cylinder is 32 : 9 and the ratio of their heights is 8 : 9. If the area of the base of the second cylinder is 616 cm2, then what will be the radius of the first cylinder ?
Answer & explanation
Correct answer: option 3
We know that,
Volume of cylinder = πr2h
We have,
Volume ratio = 32 ∶ 9
Ratio of their heights is 8 ∶ 9
Area of the base of the second cylinder = 616 cm2
Since we know that the Volume of cylinder = Area of base × height
= Volume of second cylinder = 616 × 9y
Let the radius of first cylinder be r
= base area of first cylinder = πr2
Volume of first cylinder = πr2 × 8y
Their ratios = 616 × \(\frac{9y}{(πr^2 × 8h) }\) = \(\frac{9}{32}\)
= (22r2 × 8) ×\(\frac{1}{(616 × 9 × 7)}\) = \(\frac{32}{9}\)
= r2 = (616 × 9 × 32 × 7) ×\(\frac{1}{(9 × 22 × 8)}\)
= r = 28