Q.1) The volume of a right circular cone is 37.68 dm3 .If the the base is 3 dm, find (1) the height (2) the curved surface area of the cone .( Take π=3.14)

Answer 1

V of cone = (1/3) π r^2 h
37.68 = (1/2) π (1.5)^2 h , I assume the base has a diameter of 3 dm

h = 2(37.68)/(2.25π) = .....
(you are obviously going to use your calculator, so why not use the built-in value of π in your calculator for more accuracy. Btw, don't round off h at this point, keep the value of h in your calculator's memory)

Surface area of cone = πrs, where s is the slant height
so we need s
s^2 = r^2 + h^2
= 1.5^2 + h^2 from above,
so you can find s.

sub into the surface area formula

Answer 2

The base is 3dm? I assume that is the diameter.

Volume=1/3 Base Area*height
height= 3*volume/base area=3*37.68/(PI(3/2)^2)

Surface area=PI*r*sqrt(r^2+h^2)