Question

A 20m deep well diametre 7m is dug and the earth from digging is evenly spread out to form a platform 22m×14m.find the height of the platform.(pie=22/7)
​

Answer 1

Answer:

• It is given the height of the right cylindrical shaped well is 20 m
• Diameter = 7 m

So , let us first find out the radius of the well which is given by

$r \: = \frac{d}{2}$

so,

$= > r = \frac{7}{2} \\ \\ = > r = 3.5m$

Now, we have to find the volume of the earth which is dug out from the well and this volume will be equal to the volume of the well if height 20 m and radius 3.5m ✓

$\bold{volume = \pi \: r ^{2}h }$

$= > \bold{volume = \frac{22}{7} \times 3.5 ^{2} \times 20 } \\ \\ = > \bold{volume = 3.14 \times 12.25 \times 20} \\ \\ = > \bold{volume = 769.3m ^{3} }$

So we can see that the volume of the platform is equal to the volume of the earth dug out ✓

•°•

$= > 769.3 = l \times b \times h(of \: cuboidal \: platform \\ \\ = > 769.3 = 22 \times 14 \times h \\ \\ = > \bold{ h = \frac{769.3}{308} } \\ \\ = > \bold{h = 2.49m }$

By the above calculation we find the height of the cuboidal form platform is

$\bold{2.49m}$