



 
Sara, The perimeter of a sector is composed of three pieces, an arc of the circle and two radii. You know the length of the radii so what remains is to find the length of the arc. Suppose the length of the arc is a cm and the angle at the centre of the circle subtended by the arc is θ radians. The area of the sector is then
and the length of the arc is
This is enough information to find a. Penny  


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