Question

the inner diameter of 15 metre deep circular well is 4.2 metre find the cost of plastering the its inner cover surface at the rate of rupees 40 per metre square Pi is equal to 22/7​

Answer 1

Answer:

Step-by-step explanation:

Let's consider the well a cylinder

Height =15m

Inner radius =4.2=42/10/2=2.1m

Here we have to find the lateral surface area

Lateral surface area=2×22/7×2.1×15

2×22/7×21/10×15=198sq.m

Total cost=198×40=₹7920

Answer 2

Answer:

Inner Cover Surface=7920 rupees

Step-by-step explanation:

Inner Cover Surface=2πrh

d=2r=4.2metre

r=2.1meter

h=15meter

2πrh=2×(22/7)×2.1×15

=198sq.meter

=198×40rupees

=7920rupees