Question

Two adjacent angles of a parallelogram are in the ratio 4:5.find the measure of each of its angle.

Answer 1

let each angle=x
one angle=4x
other angle=5x
4x+5x= 180degree ( adjacent angles of parallelogram are supplementary)
9x =180 degree
x = 180/9 degree
x = 20 degree
answer. one angle= 4x = 4×20 = 80 degree
another angle= 5x = 5×20 = 100 degree

Answer 2

Solution :

Let the angles be 5y and 4y.

Then ,

➨ 4y + 5y = 180° ( Co - interior )

➨ 9y = 180°

➨ y = 180/9

➨ y = 20°

 

Hence ,

4y = 4 × 20 = 80°

5y = 5 × 20 = 180°