Given that (a²+b²)=60, then find the value of (a+b)²+(a–b)².

An angle is four times its complementary angle. What is the measure of the angle?

In the figure below, find the value of AB.

What is the length of the radius of the circumcircle of the equilateral triangle, the length of whose side is 6√3 cm?

Two circles having radii 5 units intersect each other in such a way that each of them passes through the centre of the other. Then the length of their common chord is

ABCD is square and CDE is an equilateral triangle outside the square . What is the value ( in degrees ) of ∠BEC ? 

O is the incentre of ∆ABC and ∠A = 30° then ∠BOC is

In a ∆ABC ∠A : ∠B : ∠C  = 2 : 3 : 4 . A line CD drawn || to AB, then the ∠ACD is: