# How Many Cubic Meters of Earth Must Be Dug Out to Make a Well 28 M Deep and 2.8 M in Diameter ? Also, Find the Cost of Plastering Its Inner Surface at Rs 4.50 per Sq Meter. - Mathematics

Sum

How many cubic meters of earth must be dug out to make a well 28 m deep and 2.8 m in diameter ? Also, find the cost of plastering its inner surface at Rs 4.50 per sq meter.

#### Solution

Radius of the well = 2.8/2=1.4 m

"Depth of the well=28 m"

"Therefore, volume of earth dug out "=pir^2h

=22/7xx1.4xx1.4xx28

=17248/100

=172.48m^3

"Area of curved surface"=2pirh

=2xx22/7xx1.4xx28

=246.40 m^2

Cost of plastering at the rate of Rs.450 per sq m

=Rs. 2.40xx4.50

=RS 1108.80

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