Show that a parallelogram is composed of an isosceles trapezium and an isosceles triangle

Draw a parallelogram composed of a trapezium and a traingle.Label:obtuse trapezium anlges as aacute trapezium angles as bbase triangular angles as ctop triangular angle as d
By definition of a parallelogram, a = b + dBy definition of an isosceles triangle, d + 2c = 180By definition of an isosceles trapezium, 2a + 2b = 360By defition of a straight line, a + c = 180
b = a - db = a - (180 - 2c)b = (180 - c) - 180 + 2cb = cOnly possible if b and c are alternate angles within the parallelogram.b =
b = c