Question

CSA of a cone is 40y0cm sq and its diameter is 70 cm . what is its stant height.
​

Answer 1

d=70cm
∴r=35cm CSA of a cone=πrl.
4070cm
2
=
7
22
​
×35cm×l
∴
110
4070
​
=l
∴l=37cm
∴ Slant height of the cone =37cm.

Answer 2

Curved surface area of a cone =πrl, where r is the radius of the cone and l is the slant height.

Radius =

2

Diameter

=35 cm

Hence, curved surface area of this cone =

7

22

×35×l=4070

⇒l=

22×35

7×4070

⇒l=37 cm