Prove that the sum of the squares of the sides of a rhombus is equal to the sum of the squares of its diagonals.

Prove that sum of squares of the diagonals of a parallelogram is equal to sum of squares of its sides.

Prove that the are of the rhombus is half the product of the lengths of its diagonals.

Prove that in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.

Prove that the areas of the equilateral triangle described on the side of a square is equal to half the area of the equilateral triangle described on one of its diagonal.

In an equilateral triangle, prove that three times the square of one side is equal to four times the square of one of its altitudes.

Prove that the diagonals of a square are equal.

If the sum of squares of two sides is equal to square of third side then DeltaABC is

If the sum of the roots of ax^2bx +c = 0 is equal to the sum of the squares of their reciprocals, then show that c/a, a/b, b/c are in A.P.