Download Handy Theorems

Handy Theorems
1. A diagonal of a parallelogram divides the parallelogram into two congruent
triangles.
2. Opposite sides of a parallelogram are congruent.
3. Opposite angles of a parallelogram are congruent.
4. Consecutive angles of a parallelogram are supplementary
5. The diagonals of a parallelogram bisect each other.
6. A rhombus is a parallelogram.
7. A rectangle is a parallelogram.
8. The diagonals of a rhombus are perpendicular.
9. The diagonals of a rectangle are congruent.
10. The diagonals of a kite are perpendicular.
11. A square is a rectangle.
12. A square is a rhombus.
13. The diagonals of a square are congruent and are the perpendicular bisectors
of each other.
Handy Theorems for Special Quadrilaterals
1. If two pairs of opposite sides of a quadrilateral are congruent, then the
quadrilateral is a parallelogram.
2. If one pair of opposite sides of a quadrilateral are parallel and congruent,
then the quadrilateral is a parallelogram.
3. If the diagonals of a quadrilateral bisect each other, then the quadrilateral is
a parallelogram.
4. If one angle of a parallelogram is a right angle, then the parallelogram is a
rectangle.
5. If the diagonals of a parallelogram are congruent, then the parallelogram is
a rectangle.
6. If one pair of adjacent sides of a parallelogram is congruent, then the
parallelogram is a rhombus.
7. If the diagonals of a parallelogram bisect the angles of the parallelogram
then the parallelogram is a rhombus.
8. If the diagonals of a parallelogram are perpendicular, then the parallelogram
is a rhombus.