Question

2 adjacent angle from linear pair and there ratio 4:5find the angle

Answer 1

let one angle be 4x and other 5x then 4x+5x=180
$9x = 180 \\ x = 20 \\ then \: 4 \times 20 = 80 \\ 5 \times 20 = 100$

Answer 2

Let the angles 4x and 5x

Sum of two adjacent angles is 180
4x+5x=180
9x=180
X=180/9
X=20
First angle= 4*20=80
Second angle= 5*20=100