Hi Amandsa,

If a sector has central angle that measures θ degrees then the sector is a fraction of the circle. The fraction is θ/360 since the central angle for the entire circle is 360 degrees.

The area of a circle of radius r is π r² where π is approximately 3.1416. The area of a sector is a fraction of the area of the circle, in fact it's the same fraction as above so

area of a sector of a circle = θ^o/360^o × π r² square units.

The circumference of a circle of radius r is 2 π r so the length of the arc that of a sector with central angle θ is the same fraction of the circumference. Thus

the length of an arc of a circle with central angle θ = θ^o/360^o × 2 π r units.

Penny