An arc of 30 ° in one circle is double an arc in a second circle, the radius of which is three times the radius of the first. Then the angles subtended by the arc of the second circle at its center is 

In ∆ABC, ∠B is a right angle, AC = 6cm, and D is the mid-point of AC. The length of BD is:

If AD, BE and CF are medians of ∆ABC, then which one of the following statements is correct? 

The length of the common chord of two circles of radii 30 cm and 40 cm whose centers are 50 cm apart is (in cm) 

What is the area (in cm²) of the circumcircle of a triangle whose sides are 6 cm, 8 cm and 10 cm respectively?

In a circle, PQ is diameter, RS is chord of length equal to radius of circle. PR and QS when produced intersect at point T. Find the ∠PTQ?

The difference between the circumferences of two circles is 110 cm and the radius of the smaller circle is 14 cm. what is the radius of the larger circle?

If two complimentary angles are in the ratio of 4:5, find the greater angle.