Question

Diameter of a well is 2.1m and 14m deep find the cost of plastering it at ₹5 per sq. m.

Answer 1

hello!!

here's ur answer...

given:-

diameter of the well=2.1m

radius=2.1/2

=1.05m

let the height be the deep of the well.

TSA=2πr(h+r)

=2×22/7×1.05(14+1.05)

=44/7×1.05(15.05)

=46.2/7×15.05

=695.31/7

=99.33m²

cost of plastering=5×99.33

=₹496.65

hope this helps...

Answer 2

Hi ,

Let d , and h are diameter and depth of the

well ,

d = 2.1 m

radius of the well = r = d/2

r = 2.1/2 m

h = 14m

plastering area of the well = curved surface

area of the cylinder

= 2πrh

cost of plastering 1 sq m = Rs5

cost of plastering the well = 5 × 2πrh

= 5 × 2 × ( 22/7 ) × ( 2.1 /2 ) × 14

= Rs 462

I hope this helps you.

:)