Question

Please tell me with full explanation​

Answer 1

Topic

Mensuration

Given

The circumference of the base of 16m high solid cone is 33m.

To Find

Curved Surface Area of given Cone.

Formula to be used

Base of a Solid Cone is a Circle, so

Circumference will be 2πr.

Curved Surface Area of Cone = πrl

l² = h² + r² ( from Pythagoras Theorem )

where

r is radius of the base and

l is slant height of the Cone.

h is height of the Cone.

Solving

It is given that Circumference of base is 33m.

2πr = 33

2 × 22/7 × r = 33

r = 21 / 4

So, radius of the base is 21/4 metres.

Now, calculating the Slant Height

l² = h² + r²

l² = ( 16 )² + ( 21/4 )²

l² = 256 + 441/16

l² = 283.56

l = 16.84 metres

So, the slant height of the Cone is 16.84 metres.

Now, calculating the Curved Surface Area

CSA = πrl

CSA = 22/7 × 21/4 × 16.84

CSA = 277.86 m²

( CSA is Curved Surface Area )

Answer

So, the Curved Surface Area of the given solid cone is 227.86 m² which is C option.

Answer 2

Answer:

circumference of base =2πr

33=2*22/7*r

• 33*7/2*22=r
• r=5.25
• l^2=r^2+h^2
• = 5.25*5.25+16*16
• l=16.8
• curved surface area=πrl
• =22/7*5.25*16.8
• =227.84cm^2