JIPMAT (QA) PYQs

The radius of two concentric circles are 13 cm and 8 cm. AB is a diameter of the bigger circle. BD is tangent to the smaller circle touching it at D. The length AD is.

If the radius of each of four outer circles is $r$, then the radius of the innermost circle is

If the difference between the circumference and radius of a circle is 37 cm, using π = 22/7, what is the circumference (in cm) of the circle?