Question

ABCD is a trapezium if AB ll CD angle a = 74 degree and Angle B : angle C =4:5. find the measure of angles D,B and C

Answer 1

given:- AB parallel CD, angle A= 74 degree.
let the proportional quantity of B:D is 4x & 5x.
4x plus 5x = 180 ( co. int. angle)
9x = 180
x = 20.
C = 5×x = 5×20=100
B = 4×x = 4×20= 80
now,
angle D plus 74 = 180 ( co. int. angle)
D= 180- 74
D= 106.
hence, B= 80, C= 100 & D= 106


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