## Thinking Mathematically (6th Edition)

Angle $1$ is $38^\circ$ because both the lines making the angle up are parallel to the angle of $38^\circ$. Angles $1$ and $2$ add up to $90$ degrees thus Angle $2$ is $90-38=52^\circ$. Angles $1$ and $3$ add up to $180$ degrees thus Angle $3$ is $180-38=142^\circ$.