Q13 of 79 Page 229

A heap of paddy is in the form of a cone whose diameter is 4.2 m and height is 2.8 m. If the heap is to be covered exactly by a canvas to protect it from rain, then find the area of the canvas needed.

Given : Diameter of paddy = d = 4.2 m

Height of paddy = h = 2.8 m


To find : Area of canvas needed to cover paddy = ?


Formula : l =


CSA of cone = rl


Solution : radius of paddy = r = = = 2.1 m


l = = = = = 3.5 m


Area of canvas needed = CSA of cone = rl = × 2.1 × 3.5 = 23.1 m2


∴ Area of canvas needed to cover the paddy is 23.1 m2.


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