Section 4.5 – Proving Quadrilateral Properties

Theorem] A diagonal of a parallelogram divides the parallelogram in two congruent triangles.

Theorem] Opposite sides of a parallelogram are congruent

Theorem] Opposite angles of a parallelogram are congruent

Theorem] Consecutive angles of a parallelogram are supplementary

Theorem] The diagonals of a parallelogram bisect each other

Theorem] A rhombus is a parallelogram

Theorem] A rectangle is a parallelogram

Theorem] The diagonals of a rhombus are perpendicular

Theorem] The diagonals of a rectangle are congruent

Theorem] The diagonals of a kite are perpendicular

Theorem] A square is a rectangle

Theorem] A square is a rhombus

Theorem] The diagonals of a square are congruent and are the perpendicular bisectors of each other.