How many cubic metres of earth must be dug to construct a well 7m deep and of diameter 2.8m. Also find the total surface area of the well.
Answers
Answer:
Given, Earth has to dug out to make well 2.8 m in diameter and 28 m in height.
Also cost of plastering the inner wall is 4.50 per sq. m
Radius =
2
Diameter
=1.4 m
Well is cylindrical in shape.
So,
Volume of well to be dug out =πr
2
h
⇒V=
7
22
×1.4
2
×28
⇒V=172.48 m
3
To find cost of plastering of we have to first find curved surface area of inner wall.
Curved surface area =2πrh
⇒CSA=2×
7
22
×1.4×28
⇒CSA=246.4 m
2
Cost of plastering = Curved Surface Area× Rate per sq. meter
Cost =246.4×Rs. 4.50
⇒ Cost =Rs.1108.8
HOPE IT HELPS YOU!!
Step-by-step explanation:
Correct option is C)
Given, Earth has to dug out to make well 2.8 m in diameter and 28 m in height.
Also cost of plastering the inner wall is 4.50 per sq. m
Radius =
2
Diameter
=1.4 m
Well is cylindrical in shape.
So,
Volume of well to be dug out =πr
2
h
⇒V=
7
22
×1.4
2
×28
⇒V=172.48 m
3
To find cost of plastering of we have to first find curved surface area of inner wall.
Curved surface area =2πrh
⇒CSA=2×
7
22
×1.4×28
⇒CSA=246.4 m
2
Cost of plastering = Curved Surface Area× Rate per sq. meter
Cost =246.4×Rs. 4.50