Question

In the parallelogram ABCD above, angle A = 2x - 10, angle B = 3x + 20. Find the value of x, and the measure of angle B.

Answer 1

x = 34°

angle B = 122°

Step-by-step explanation:

sum of all angles of a parallelogram = 360°

angle A = angle C ( opposite angles of a parallelogram are equal)

Similarly, angle A = angle D

therefore,

angle A + angle B + angle C + angle D = 360°

=> 2(angle A) + 2(angle B) = 360

=> 2(2x-10) + 2(3x+20) = 360°

=> 4x-20+6x+40=360°

=> 10x+20=360°

=> 10x=360°-20°

=> 10x=340°

=> x=340°/10

=> x=34°

angle B = 3x+20

= 3(34)+20

= 122°

Therefore, value of x=34 and angle B=122°

Hope this helps