the diameter of sphere is decreased by25% by what percent does its curved surface area decreases
Answers
Answered by
1
Answer:
Original Diameter =d
Original CSA=4π(
2
d
)
2
=πd
2
New Diameter =d−
100
25
d=
4
3d
New CSA=4π(
8
3d
)
2
=
16
9
πd
2
.
% decrease =
πd
2
(πd
2
−
16
9
πd
2
)
×100
=
πd
2
πd
2
(1−
16
9
)×100
=
16
16−9
×100
=43.75%.
Answered by
1
Answer:
The diameter of a sphere is decreased by 25%. By what per cent does its curved surface area decrease? cm. Hence, the original curved surface area decreases by 43.75%.
OR
Original Diameter =d
Original CSA=4π(
2
d
)
2
=πd
2
New Diameter =d−
100
25
d=
4
3d
New CSA=4π(
8
3d
)
2
=
16
9
πd
2
.
% decrease =
πd
2
(πd
2
−
16
9
πd
2
)
×100
=
πd
2
πd
2
(1−
16
9
)×100
=
16
16−9
×100
=43.75%.
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