Question

The diameter of a circular wall is 4.5m and it's depth is 14m.find the cost of cementing the inner surface of the wall at ₹120 per square.m

Answer 1

Solution:–

★ Radius = Diameter/2

★ Radius = 4.5/2 = 2.25 m

➫ Radius = 2.25 m

Here the well is to be cemented from inside therefore we have to find the CSA of the wall which is in the shape of a cylinder.

We know that:–

★ CSA of Cylinder = 2πrh

⟹ CSA of Well = 2(22/7)(2.25)(14)

⟹ 44(2.25)(2)

⟹ 44 × 4.5

⟹ 198 m²

➫ CSA of Cylinder = 198 m²

Now,

★ Cost of cementing 1 m² well = ₹ 120

Cost of cementing 198m² well =198×120

➫ Total cost will be = ₹ 23760.

∴Your Answer = ₹23760