Question

find the total surface area of a cone, if its slant height is 21m and diameter is 24m​

Answer 1

Answer:

Given,

Slant height of cone is l=21 m.

Diameter of its base is d=24 m.

hence, radius of its base is r= 2d

=12 m.

Now, the total surface area of cone is given by

S=πrl+πr 2

S=π(rl+r 2 )

S=π(12×21+12 2 )

S=π(252+144)

S= 722×396

hence, S=1244.57 m

It is a help ful