A bucket is in the form of a frustum of a cone and its can hold 28.49 litres of water. If the radii of its circular ends are 28 cm and 21 cm, find the height of the bucket.
Given: volume of bucket = 28.49 litres
1 litre = 1000 cm3
∴ 28.49 litres = 28.49 × 1000 cm3
∴ Volume of bucket = 28490 cm3
Radius of upper circular end = R = 28 cm
Radius of lower circular end = r = 21 cm
Let ‘h’ be the height of the bucket
Volume of bucket = volume of frustum of cone
∴ 28490 × 21 = h × 22 × (784 + 441 + 588)
∴ h = 598290/39886 cm
∴ h = 15 cm
∴ Height of bucket = h = 15 cm
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