Question

A cylindrical hole of depth 20 m with a radius 5 m is dug from the earth forming a platform of length 14 m and a breadth of 12 m. Find the height of the platform.

(a) 8.34 m^3

(b) 11.84 m^3

(c) 7.64 m^3

(d) 9.34 m^3

I had been asked this question by my school principal while I was bunking the class.

This key question is from Conversion of Solid from One Shape to Another in portion Surface Area and Volumes of Mathematics – Class 10

Answer 1

Right choice is (d) 9.34 m^3

To elaborate: Volume of the cylindrical hole = volume of the platform

πr^2h = lbh

3.14 × 5^2 × 20 = 14 × 12 × h

h = 9.34 m^3