Question

In a parallelogram abcd ,angle a=x° angle b=(3x +20).Find x and anglec and angle d

Answer 1

angle a = x
angle b = 3x + 20
angle a + angle b = 180 .....( Co interior angles)
x+ 3x+20= 180
4x + 20 = 180
4x = 180-20
4x = 160
x = 160/4
x = 40
Therefore,
angle a = 40
angle b = 3(40)+20= 140
angle a = angle c = 40(opposite angles are equal in a parallelogram)
similarly,
angle b = angle d = 140

Hope it helps you..