SOLUTION: A circular sector AOB, centre O and radius 8 cm, contains an angle of {{{3pi/4}}} radians at the centre. The straight edges OA and OB are joined to form a right circular cone. Find

Algebra ->  Surface-area -> SOLUTION: A circular sector AOB, centre O and radius 8 cm, contains an angle of {{{3pi/4}}} radians at the centre. The straight edges OA and OB are joined to form a right circular cone. Find      Log On


   

Question 1117754: A circular sector AOB, centre O and radius 8 cm, contains an angle of 3pi%2F4 radians at the centre. The straight edges OA and OB are joined to form a right circular cone. Find the radius of the base of the cone.
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The central angle is 3/8 of the complete circle, so the circular arc is 3/8 of the circumference:

%283%2F8%29%288%29%282pi%29+=+6pi

When the cone is formed, that 6pi is the circumference of the base.

Then the radius of the base is 6pi%2F%282pi%29+=+3