find the curved surface area of cone using the given figure. given base diameter 12 cm and the angle at the conical vertices is 120

Asked by  | 27th Feb, 2013, 12:14: PM

Expert Answer:

Radius of the cone = 12/2 cm = 6 cm
Apex angle = 120
Slant height(l) = radius/sin(120/2) (Considering trignometry in the cone triangle)
l = 6/sin60
l = 12/sqrt(3)
l = 4*sqrt(3)
 
Curved surface area of a cone = pi*r*l = pi * 6*4*sqrt(3) = 130.53 cm2

Answered by  | 28th Feb, 2013, 06:03: AM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.