A bucket is in the form of a frustum of a cone and it can hold 28.49 liters of water. If the radii of its circular ends are 28 cm and 21 cm, find the height of the bucket. [Use π=22/7].

Let the height of the bucket be h cm.
Suppose r1 and r2 be the radii of the circular ends of the bucket.
Given, r1 = 28 cm and r2 = 21 cm
Capacity of bucket = 28.49 liters
Therefore, Volume of the bucket = 28.49 × 1000 [1 litre = 1000 cm³]
⇒ 1/3 πh(r1² + r2² + r1r2) = 28.49 × 1000
⇒ 1/3 × 22/7 × h × [28² + 21² + 28 × 21] = 28490
⇒ 22/21 × h × [784 + 441 + 588] = 28490
⇒ 22/21 × h × 1813 = 28490
⇒ h = 28490 × 21 / 22 × 1813
⇒ h = 15 cm
Therefore, the height of the bucket is 15 cm.