Class 9 – Quadrilaterals

Theorem 8.10: The line drawn through the mid-point of one side of a triangle, parallel to another side bisects the third side. Theorem 8.9 Class 9 | Home

Theorem 8.9: The line segment joining the mid-points of two sides of a triangle is parallel to the third side. Theorem 8.8 Theorem 8.10

Theorem 8.8: A quadrilateral is a parallelogram if a pair of opposite sides is equal and parallel. Theorem 8.7 Theorem 8.9

Theorem 8.7: If the diagonals of a quadrilateral bisect each other, then it is a parallelogram. Theorem 8.6 Theorem 8.8

Theorem 8.6: The diagonals of a parallelogram bisect each other. Theorem 8.5 Theorem 8.7

Theorem 8.5: If in a quadrilateral, each pair of opposite angles is equal, then it is a parallelogram. Theorem 8.4 Theorem 8.6

Theorem 8.4: In a parallelogram, opposite angles are equal. Theorem 8.3 Theorem 8.5

Theorem 8.3: If each pair of opposite sides of a quadrilateral is equal, then it is a parallelogram. Theorem 8.2 Theorem 8.4

Theorem 8.2: In a parallelogram, opposite sides are equal. Theorem 8.1 Theorem 8.3