Since length of tangents drawn from a particular point to the circle is equal, by solving we get QR is equal to PS.
Hence PQRS is an isosceles trapezium.
Drawing perpendicular from P to SR intersecting at A and Q to SR intersecting at B.
Hence in right angled Δ PSA, PS = 25, SA = 7. Hence PA = 24. Height PA = 24 cm.
Therefore, diameter of circle is 24 cm.