Question

A well of diameter 150 cm has a 30 cm wide parapet running around it. Find the area of the parapet. (Steps to be shown please)
(Please answer it fast!!! Its very urgent!!)

Answer 1

Given diameter = 150cm. 

Then the radius will be r = d/2

                                         = 75 cm.

Given width = 30cm.

Outer radius of the parapet R = 75 + 30

                                                  = 105 cm.


The area of the parapet = pi(R^2 - r^2)

                                         = pi((105)^2 - (75)^2)

                                         = 22/7 * (11025 - 5625)

                                          = 22/7 * 5400

                                          = 16971.428 cm^2.


Hope this helps!

Answer 2

Answer:

Diameter of well = 150 cm

Radius of well = 75 cm

Area of well Aw = pi*r*r

= 22/7*75*75

Area of outer space Ao = pi*R*R

= 22/7*(105)*(105)

Area of parapet = Ao - Aw

= 22/7*15*15(7*7 - 5*5)

= 22/7*15*15(24)

= 16971.4 cm^2