Any given circle represent an angle of 360 degrees at a point (the center of the circle). Therefore the area of a sector is given by the fraction of the angle the sector subtends at the center to the total angle (360) multiplied by the total area. Therefore the are of sector DCA ( subtends 120 degrees) is a fraction of 120 ÷ 360 = 1/3. Expressing this as a percentage 1/3× 100 = 33.333 which is approximately 33 degrees. Thus area of sector DCA represents 33% of the total area of the circle.
