Question

Find the volume,curved surface area and the total surface area of a cone having base radious 35cm and hieght 84cm

Answer 1

Heya friend!
Rajdeep here....

h = 84cm
r = 35 cm

V = $\frac{ \pi r^{2}h}{3}$
= 3.14 x 35 x 35 x 84 / 3
= 107702 cm^3

Slant height l = [tex] \sqrt{(84)^{2} + (35)^{2}} \\ = \sqrt{7056 + 1225} \\ = \sqrt{8281} \\ = 91 cm [/tex]

So CSA = [tex] \pi rl [/tex]
= 3.14x35x91
= 10000.9 cm^2

TSA = CSA + Base area
= [tex] \pi rl + \pi r^{2} \\= \pi r(l+r)[/tex]
= 3.14x35(91+35)
= 3.14x35x126
= 13847.4 cm^2

Thanks!

Answer 2

r=35  h=84
h^2+r^2=l^2
84^2+35^2=l^2
7056+1225=8281
l=91 cm
V=1/3 pi r^2 h
  = 107799.99 cm^3
CSA = pi r l
        = 10009.99 cm^2
TSA = pi r (r+l)
        = 13860.0 cm^2