Question

please solve this question.

Answer 1

Take a point O on circle and join all the vertices.
Height=√(slant height)^2-(radius)^2=9 cm
Let the vertices of cone be A,B,and C
Height=AM
So area of ∆ABC =1/2×AM×BC =1/2(6√3)(9)=27√3..(i)
Also let the radius be r
So,area of
∆ABC=ar(∆AOB)+ar(∆AOC)+ar(∆BOC)
=1/2(6√3)r+1/2(6√3)r+1/2(6√3)r
=1/2(r)18√3=9√3r..(ii)
Equating equations i andiiwe get
=>r=3
So, option (D) r=3 is correct

Answer 2

Excuse my Figure, I hope you can understand!