In fig 12.30, OACB is a quadrant of a circle with centre and radius 3.5 cm. If OD=2 cm find the area of the (1) quadrant OACB, (ii) shaded region. (ii) shaded region. In fig 12.30 OACB is a quadrant of a circle with centre and radius 3.5 cm. If OD=2 cm find the area [...]