In △PQR, ∠P = 90°. S and T are the mid points of sides PR and PQ, respectively. What is the value of RQ²/(QS²+ RT²)?

If the area of a circle is 9π sq.cm then it circumference is

5√2 cm in a circle. If the long chord makes a right angle at the centre, then what will be the length of the radius of the circle?

In a quadrilateral ABCD, E is a point in the interior of the quadrilateral such that DE and CE are the bisectors of ∠D and ∠C, respectively. If ∠B = 82° and ∠DEC = 80°, then ∠A = ?

Triangle PQR is such that PQ=9 cm, QR=6 cm, PR=7.5 cm and triangle PQR is similar to triangle XYZ. If XY=18 cm, find the value of YZ.

If radius of a sphere is decreased by 48%, then by what percent does its surface area decrease?

PAB and PCD are two secants to a circle . If PA 10 cm , AB = 12 cm and PC = 11 cm , then what is the value ( in cm ) of PD ?

What can be the maximum number of common tangent, which can be drawn to two non-intersecting circles?