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

How many spherical bullets each of 4cm in diameter can be made out of a cube of lead whose edge is 44cm?

The area of a trapezium is 336cm².If its parallel sides are in the ratio 5:7 and the perpendicular distance between them is 14cm,then the smaller of the parallel sides are

If the surface area of a cube is 13254cm²,length of the diagonal is