All quadrilaterals has a total measure of angle
equal to 360 degrees. In the parallelogram ABCD, m<B = m<D = 41. So if
m<B = m<D = 41, we have 41 + 41 = 82 degrees. Since the parallelogram is
a quadrilateral, it has a total measure of angle of 360 degrees. So 360 – 82 is
equal to 278 degrees. If the measure of angle C is equal to the measure of
angle A, divide 278 by 2. We get 139 degrees. To confirm if the parallelogram
ABCD has a total measure of 360 degrees, add 41 + 41 + 139 + 139 = 360 degrees.
