1.find the volume, area of the curved surface and the total surface area of a cylinder whose height and radius of base are 20 cm and 28 CM respectively.
2.the diameter of a roller is 2.1 metre and its length is 1.75 metre if it takes 500 revolutions to level a field find the cost of levelling it at 75 paise per metre ²
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1)
given:
h = height = 20cm
r = radius = 28cm
to find:
volume , tsa , csa
Sol.
volume of cylinder =
= 22/7 * 28 * 28 * 20 cm^3
= 22 * 4 * 28 * 20 cm^3
= 49280 cm^3
or , 49.28 l
csa of cylinder =
= 2 * 22/7 * 28 * 20
= 2* 22 * 4 * 20
= 3520cm^2
tsa of cylinder =
= 3520 + 2 * 22/7 * 28 * 28
= 3520 + 2 * 22 * 4 *28
= 3520 + 4928
= 8448cm^2
2)
given:
d = diameter = 2.1 m
h = length = 1.75 m
revolutions = 500
and cost of leveling per m^2 is Rs 0.75/-
to find:
total cost of leveling
Sol.
total area covered = csa * total no. of revolutions
=
=
= 22/7 * 2.1 * 1.75 * 500
= 22 * 0.3 * 1,75 *500 m^2
now , total cost = cost of leveling a m^2 * total area
= 22* 0.3 * 1.75 * 500 * 0.75
= Rs 4331.25/-
CALCULATION :-
Given that
So,
Now,
Now,
Given that
So,
And
Now,
We know that,
Now,
Cost of levelling the field is Rs 0.75 per square metre.
So,
Total Cost of levelling the field is