In the diagram, DC is a diameter of large circle centered at 'A' and AC is a diameter of smaller circle centered at B. If DE is a tangent to the smaller circle at F and `DC=12` . Then length of DE is

If the diagram, D C is a diameter of the large circle centered at A , and A C is a diameter of the smaller circle centered at B . If D E is tangent to the smaller circle at F and D C=12 then the length of D E is .

The radii of two concentric circles are 13 cm and 8 cm. AB is a diameter of the bigger circle. BD is a tangent to the smaller circle touching it at D. Find AD.

AB is the diameter of a circle whose centre is O. DC is a chord of that circle. If DC||AB and angleBAC=20^(@) then angleADC =?

The radii of two concentric circle are 13 cm and 8 cm. AB is a diameter of the bigger circle and BD is a tangent to the smaller circle touching it at D and the bigger circle at E. Point A is joined to D. Find the length of AD.

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.