Two supplementary angles equal 180 degrees.
Let the first angle = x
The second angle is 30 degrees more so this would be x + 30
Now add the two angles together to equal 180:
X + x+ 30 = 100
Combine like terms:
2x + 30 = 180
Subtract 30 from both sides:
2x = 150
Divide both sides by 2:
X = 75
One angle = x = 75
The other angle is x + 30 = 75 + 30 = 105
The smaller angle is 75 degrees.