Statement
The diagonals of a square are equal and perpendicular to each other.

Given:
ABCD is a square.
AC and BD are diagonals intersecting at O.To prove:

Proof:
AB=AD (sides of a square are equal)AB||DC (opposite sides of a square are parallel)
ABCD is parallelogram with consecutive sides equal.
ABCD is a rhombus. (by definition)
ABCD is a parallelogram.
ABCD is a rectangle with a pair of its consecutive sides equal.
Diagonal AC=Diagonal BD and AC ^ BD
