Areas of Parallelograms
* Area of a parallelogram is equal to the product of its base and corresponding height.
* The diagonal of a parallelogram bisect each other.
* A diagonal of the parallelogram divides it into two congruent triangles.
* Opposite sides and angles of a parallelogram are equal.
* Two congruent figures have equal areas but the converse need not be true.
* Parallelograms on the same base (or equal bases) and between the same parallels are equal in area.
* Parallelograms on the same base (or equal bases) that have equal areas lie between the same parallels.
* If a parallelogram and a triangle are on the same base and they are between the same parallels, then area of the triangle is half the area of the parallelogram.
Area of Triangles
* Triangles on the same base (or equal bases) and between the same parallels are equal in area.
* Triangles on the same base (or equal bases) and having equal areas lie between the same parallels.
* A median of a triangle divides it into two triangles of equal areas.