Question

Abcd is a parallelogram if the two sides are equal find the measure of angle abc

Answer 1

ABCD is parallelogram if two side are equal
AD=BC
(Opposite side are equal)
so AB=BA
DB=CA
angle ADB =angle BCA
so angle DAB= angle CBA----(1)
but AD is parallel to BC
so, angle DAB+ angle CBA=180°
sum of consecutive interior angle on the same side of a transvarsal 180°
CAB + CBA =180°
2CAB =180
CAB = 90°
So, ABC=90
Answer solve