A B and CD are respectively arcs of two concentric circles of radii 21 CM and 7cm which center O(see figure).If`/_=30^@` find the area of the shaded region. ( use`pi=22/7`)

AB and CD are respectively arcs of two concentric circles of radii 21 cm and 7 cm . With centre O (See figure ). If angleAOB=30^(@) ,find the area of the shaded region . (use pi=(22)/(7) )

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 (use pi=22/7 )

In figure 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 . (use pi=(22)/(7) )

The given figure consists of four small semi-circles of equal radii and two big semi-circles of equal radil (each 42 cm). Find the area of the shaded region.

The given figure consists of four half circles and two quarter circles. If OA OB=OC=OD=14 cm. Find the area of the shaded region.

Two concentric circles of radii 10 cm and 6 cm are drawn . Find the length of the chord of the larger circle which touches the smaller circle .

Two concentric circles of radii 5 cm and 3 cm are draw . Find the length of the chord of the larger circle which touches the smaller circle .

Two concentric circles of radii 25 cm and 24 cm are drawn. Find the length of the chord of the larger circle which touches the smaller circle.

Two circles of radii 7 cm and 4 cm touch each other externally. Then the distance between their centres.

In the given figure A, B, C and D are centres of equal circles which touch externally in pairs and ABCD is a square of side 7 cm. Find the area of the shaded region.