Angle 1 and 2 are supplementary angles and need to equal 180 degrees.
Since angle 2 is given as 57, subtract 57 from 180 to find angle 1.
Angle 1 = 180 - 57 = 123 degrees.
We know that if we remove the line that cuts the horizontal line, we would have an angle of 180º and we also know that the 2nd angle measures 57º. Therefore, we calculate the difference:
180º - 57º = 123º
∠1 - 123º
∠2 - 57º
Hope it helped,
BioTeacher101
