Question

A 20 cm deep well with daimeter 7 cm is dug the earth from digging is evenly spread out to form a platform 22 cm by 14 cm . find the height of platform

Answer 1

depth of well, h = 20cm
radius of well, r = 7/2 cm

dimension of platform base = 22cm × 14 cm
height of platform = H


Volume of the well = volume of the platform

πr^2h = 22×14×H

22/7 × 7/2 × 7/2 × 7 = 22×14×H

H = 7×7/(2×2×14) cm

H = 7/8 cm

Height of platform is 7/8 cm

Answer 2

⇒ Given:- Height (h) of well :- 20m

Diameter (d) :- 7 m

Radius (r) :- 7/2 m

Volume of earth platform :- 22 m by 14m

⇒ To find :- Height of the platform:- ?

⇒ Solution:-

Volume of cylinder of radius 7/2 m and height 20 m

Volume of cylinder :- π(r^2)(h)

= 22/7×(7/2^2)×20 m^3

= 770 m^3

Let the height raised by 22 m × 14 m platform be equal to h metres

Therefore,

Volume of the earth in platform = Volume of the earth taken out of the well

22 × 14 × h = 770

h = 770/22 × 14 m

h = 5/2 m

h = 2.5 m

Hence , the height of the platform is 2.5 m.