Supplementary angles
The question
degrees
Angles on a straight line, one is 25°
How it works.
25°+x=180°
180 − 25 =155°
25°+155°=180°
from the picture, not the numbers
lines crossing:x = the angle opposite
- 01
The two angles sit on a straight line, and a straight line is 180°.
- 02
So the two must add to 180: x = 180 − 25 = 155°.
- 03
Check it: 25 + 155 = 180.
- 04
Good to know too: where two lines cross, the angles facing each other are equal.