SOLUTION: A sector of a circle has an angle at the centre of pi/4 and a perimeter of 12. Work out the radius of the circle.
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Question 854810: A sector of a circle has an angle at the centre of pi/4 and a perimeter of 12. Work out the radius of the circle.
Answer by josgarithmetic(39616) (Show Source): You can put this solution on YOUR website!
r is the unknown radius.
The circumference (of the circle) would be 2*pi*r, and the arc length portion of the sector is ; which we should simplify NOW:
The perimeter of the sector is the sum of two of r and the ArcPortion:
Given that the perimeter is 12,
This is now a fairly simple equation easily solvable for r.
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