A circle of radius r is inscribed in a regular polygon with n sides.If the perimeter of the polygon is p,area of the polygon is

Chord CD intersects the diameter of the circle at right angle to the point P in the ratio 1:2.If  diameter of the circle is d,then CD is equal to 

In the above figure,ABCD is a parallelogram.P is a point on BC such that PB:PC=1:2.DP and AB when both produced meet at Q.If area of triangle BPQ is 20 square unit,the area of triangle DCP is

From an external point P,tangents PA and PB are drawn to the circles as shown in the above figure.CD is the tangent to the circle at point E.If AP=16cm,then the perimeter of the triangle PCD is equal to

AB is a line segment of length 2a,with M as midpoint.Semicircles are drawn on one side with AM,MB and AB as diameter as shown in the above figure.A circle with centre O and radius r is drawn such that this circle touches all the three semi-circles.The value of r is

A river 2.5m deep and 45 m wide is flowing at the speed of  3.6km/hr.The amount of water that runs into the sea per minute is