Question

A cone is 9cm high and has vertical angle of 60 then the diameter of it's base is. A) 3√3. B) 6√3. C) 9√3. D)18√3. ?

Answer 1

1. A right cone has its vertex above the center of its base. We know that when used without qualification, the term "cone" implies "right cone."
2. The term "vertical angle", is not clear. Assuming that it refers to the opening angle which is the angle at top of cone.

Let `r` be radius of the given right cone.

`tan(60/2)="height"/"radius"=9/r`
`=>r=9/tan30`
`=>r=9sqrt3`
`:."diameter"=2r=18sqrt3\ cm`