AB and CD are respectively arcs of two concentric circle of 21 cm and 7 cm radii and centre O (see Fig). If `angleAOB=30^(@),` find the area of the shaded region.

Two concentric circles of radii 3.5 cm and 7cm form a sector as shown in the figure. Find the area of the shaded region.

Find the area of the shaded region in fig if radii of the two concentric circles with centre O are 7 cm and 14 cm respectively and lfloorAOC=40^(@) OR Find the area of the shaded region in fig. if ABCD is a square of side 14 cm and APD and BPC are semi circles.

AB and CD are two diameters of a circle perpendicular to each other and OD is the diameter of the smaller circle. If OA = 7 cm, find the area of the shaded region.

In fig., sectors of two concentric circles of radii 7 cm and 3.5 cm are given. Find the area of shaded region. ("Use " pi = (22)/(7))

In Fig, OACB is a quadrant of a circle with centre O and radius 3.5 cm. If OD = 2 cm, find the area of the shaded region.

In the figure , ABCD is a square of side 14 cm. A, B, C and D are the centres of four congruent circle such that each circle touches externally two of the remaining three circles . Find the area of the shaded reginon.

In the given figure, there are two concentric circles of radii 6 cm and 4 cm with centre O. If AP is a tangent to the larger circle and BP to the smaller circle and the length of AP=8cm , find BP

In the given fig OACB is a quadrnat of a circle with centre O and radius 3.5 cm . If OD = 2cm find the area of the shadded region .

The areas of two concentric circles are 962.5cm^2 and 1386 cm^2 respectively. What is the width of the ring?

In Fig, a square OABC is incribed in a quadrant OPBQ. If OA = 20 cm, find the area of the shaded region ("Use"pi=3.14)