Question

Radius of base of a cylinder is 12 cm and its height is 9 cm, find its curved surface area

and total surface area, (π = 3.14)

​

Answer 1

Answer:

R.E.F image

OA=16cm,AB=l

l=

16

2

+12

2

=

256+144

l=20cm

curved surface Area,

C.S.A=πrl=3.14×12×20=753.6cm

2

Total surface Area,

T.S.A=πr(r+l)=3.14×12[12+20]=1205.76cm

2

Answer 2

Answer:

done by using the formula l2=r2+h2, where h is height.

So, l=r2+h2 =52+122=13

We have curved surface area of a cone is πrl =π×5×13 =65π cm2

Hence, the answer is 65π cm2.

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