# A Well is Dug 20 M Deep and It Has a Diameter of 7 M. the Earth Which is So Dug Out is Spread Out on a Rectangular Plot 22 M Long and 14 M Broad. What is the Height of the Platform So Formed? - Mathematics

Sum

A well is dug 20 m deep and it has a diameter of 7 m. The earth which is so dug out is spread out on a rectangular plot 22 m long and 14 m broad. What is the height of the platform so formed?

#### Solution

Height of the well = h m = 20 m
Diameter of the well = d m =7 m
Radius of the well = r m = 3.5 m
Volume of the well = πr2h = 22(3.5)2(20 ) m3= 770 m3
​                                                  7
Volume of the well = Volume of the rectangular plot
Length of the rectangular plot = 22 m
Breadth of the rectangular plot =14 m
Volume of the rectangular plot = 770 m3 = (Length x Breadth x Height) of the rectangular plot $\text{ Height }= \frac{770}{22 \times 14} = 2 . 5 m$
Thus, the height of the platform is 2.5 m.

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#### APPEARS IN

RD Sharma Class 8 Maths
Chapter 22 Mensuration - III (Surface Area and Volume of a Right Circular Cylinder)
Exercise 22.2 | Q 21 | Page 26