a diagonal of parallelogram divides it into two congruent triangle
Answers
Parallelogram Theorem #1: Each diagonal of a parallelogram divides the parallelogram into two congruent triangles.
Parallelogram Theorem #2: The opposite sides of a parallelogram are congruent. ... You can show that alternate interior angles are congruent and hence lines are parallel for this part of the proof.
Step-by-step explanation:
To Prove :-
Diagonal of a parallelogram divide it into two congruent triangles .
Solution :-
Given :-
ABCD is a parallelogram . AC is the diagonal .
To prove :-
∆ ADC congruent to ∆ ABC
Proof :-
Opposite sides of a parallelogram are parallel to each other . So,
DC || AB
AD is transverse line . So,
Angle DAC = Angle ACB .
Angle DCA = Angle CAB
In triangle ADC and triangle ABC
AD = AD. ( common )
Angle DAC = Angle ACB ( Proved above)
Angle DCA = Angle CAB ( Proved above)
By ASA criteria .
∆ ADC is congruent ∆ ABC .
Hence proved