Question

suppose ABCD is parallelogram in which A=108 degree calculate c=?

Answer 1

In a parallelogram, the opposite sides are parallel; and, the opposite angles sums to give 180 degree.
Therefore, 108+x=180
Therefore, x=72 degree.
Therefore, angle C=72 degree.

Thank you.
Hope this will help you.

Answer 2

ON a parallelogram opposite sides will be concurrent (or supplementry)
 so
 C=180-108
    =72

so C=72 degree