The area of a circle is proportional to the square of its radius. A small circle of radius 3 cm is drawn within a larger circle of radius 5 cm. Find the ratio of the difference between the area of the larger circle and that of the smaller circle to the area of the larger circle.

In any triangle ABC, AB + BC = 12 cm, BC + CA = 14 cm and CA + AB = 18 cm. What will be length of radius of a circle, if the perimeter of circle is equal to the perimeter of triangle ABC? 

In a triangle ΔABC, the sides DE parallel to BC and AD = 6 cm, DB = 9 cm, AE = 8 cm, find the value of AC.

Find the area of the largest triangle made in a semicircle of r cm radius?

In △ABC, M and N are the points on side BC such that AM ⊥ BC, AN is the bisector of ∠A, and M lies between B and N. If ∠B = 68°, and ∠C=26°, then the measure of ∠MAN is:

The maximum number of common tangents drawn to two circles when both the circles touch each other externally is 

The sum of all interior angles of a regular polygon is twice the sum of all its exterior angles.  The number of sides of the polygon is

If the circumradius of an equilateral triangle ABC is 8 cm, then what is the height of the triangle?