DRDO Multi tasking staff Model paper 2

Formula: Volume of a right circular cone =

πr2h

3

And area of curved surface of right circular cone = πrl
Given: volume = 1232 cm3
Height = 24 cm
∴ =

πr2h

3

=1232
⇒

22

7

×r2×

24

3

=1232
⇒r2=

1232×7

22×8

=49
⇒ r = 7 cm
By Pythagoras theorem, l=√r2+h2
∴l=√72+242
l = 25 cm
Now, area of curved surface = πrl
∴ Curved surface area =

22

7

×7×25=550cm2