A diagonal of a parallelogram divides it into two congruent triangles.
Theorem 1
A diagonal of a parallelogram divides it into two congruent triangles.Statements |
Reasons |
In△ABC and △CDA | |
1. ∠BAC=∠ACD | 1.Alt.∠s,AB∠DC and AC is transversal. |
2.∠BCA=∠CAD | 2. Alternate ∠s, BC∠AD and AC is transversal. |
3. AC=CA |
3. Common |
4.△ABC≌△CDA | 4. ASA congruency rule |