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

Prove that the sum of the squares of the diagonals of a parallelogram

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