a bucket is in the form of frustum of a cone whose raddi of bottom and top are 7cm and 28cm respectively. If the capacity of the bucket is 21560 cubic cm, find the whole surface area of the bucket.

  • 3

let the radii = r, R
r = 7cm ; R = 28cm
volume of bucket = 21560cm3
π/3 * h(r2 + R2 +rR) = 21560
22/21 * h (49 + 784 + 196) = 21560
h* 22*1029/21 = 21560
h = 21560/22 *21/ 1029
h = 20cm
l2 = h2 + (R -r)2
l2 = 400 + 441 = 841
l = 29 cm
SA of bucket = CSA + area of bottom
  = πl(R + r) + πr2

  = π(35 + 49) = 22/7 * 84
  = 264 cm2

  • -19
One Doubt. How does it become pi*(35+49)? Din't you multiply the slant height? I Had the Solution ready but it showed error exceptionally long words. The correct answer would be 3344 cm2.
  • 9
correct answer is 7656
  • -7
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