Question

Q. 4 Do as directed (Any Two)
(8)
(1) Find the slant height and the curved surface area of acone, if its base radius
is 8 cm and height is 15 cm​

Answer 1

Answer:

When two cones of same base are joined together, the surface of the shape formed will only have the curved surfaced areas visible.

We know that curved surface area of a cone =πrl where r is the radius of the cone and l is the slant height.

As both the cones have the same base and height, they are identical and their curved surface areas are equal.

Hence, surface area of this shape = Curved surface area of Cone 1 + Curved surface area of Cone 2=2×(πrl)

Given, r =c cm and h =15 cm

⇒l= r 2+hh= 8 2+15 2 =

64+225 =17 cm

Surface area of this shape =2×(πrl)=

2×22/7×8×17≅855cm2