Question

The entire surface of a solid cone of base radius 3 cm and height 4 cm is equal to the entire surface of a solid right circular cylinder of diameter 4 cm. Find the ratio of their (1) Curved surface areas (ii) Volumes​

Answer 1

Answer:

Correct option is D)

l=32+42=5

Total surface area of remaining solid

=CSA of cone +CSA of cylinder + area of base of cylinder

=πrl+2πrh+πr2

=πr(l+2h+r)

=π×3×(5+2×4+3)

=π×3×16

=48πcm2

Answer 2

Answer :

Correct option is D)

Given Solid cylinder whose height 4 cm and radius 3 cm

Then volume of cylinder =πr

2

h=π(3)

2

(4)=36πsq cm

And cut conical cavity height 4 cm and radius 3 cm

Then volume =

3

1

πr

2

h=

3

1

π(3)

2

(4)=12πsq cm

Then remaining part =36π−12π=24πcm

2

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