of the area of the circle. \(A = \frac{135}{360} \times π \times 4^2\) \(A = 18.85 (2 d.p.)\) Calculate the perimeter of the sector. The perimeter is made up of an arc and two straight sides.

THE usual text-book formula for the radial distance of the centroid of a circular arc of radius r and length 2ra, may be converted into a useful result by expressing the position of the centroid ...