the inner diameter of a circular well is 2.8m. it is 8m deep. find the cost of plastering the inner curved surface at the rate of 60 rupee per square metre.
arnavarun111:
7 th class
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Diameter= 2.8m
Therefore,
Radius= 2.8/2 (since radius is half of diameter)
=>1.4m
Now, Internal Curved Surface Area of a Hollow Cylinder(well) = 2πrh
=> 2 *(22/7 * 1.4 * 8)
=> 70.4m²
Now, 1 m² plastering costs = ₹60 => 70.4m² plastering costs = 60 * 70.4
=> ₹4,224 [ans.]
Therefore,
Radius= 2.8/2 (since radius is half of diameter)
=>1.4m
Now, Internal Curved Surface Area of a Hollow Cylinder(well) = 2πrh
=> 2 *(22/7 * 1.4 * 8)
=> 70.4m²
Now, 1 m² plastering costs = ₹60 => 70.4m² plastering costs = 60 * 70.4
=> ₹4,224 [ans.]
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