Question

prove that a diagonal of a parllelogram divides t into congrunt triangles

Answer 1

Consider Δ's ABC and ADC
AB = CD {Opposite sides of a parallogram}
BC = AD {Opposite sides of a parallogram}
AC = AC (Common side)
By SSS Congruence axiom,
ΔABC ≅ ΔADC
Hence ar(ΔABC) = ar(ΔADC) [Since congruent figures have same area]

Answer 2

hey.. here is ur ans...

In triangles ABD and BCD:-
AB=CD [opp. sides of parallelogram are equal]
angleA=angleC[opp. angles are equal]
AD=BC[opp. sides are equal]
so,triangles ABD=BCD (SAS criteria)

since, diagonal of a parallelogram divide it into two congruent triangles