Notice that angles 1 and the given angle with measure 68° are corresponding angles, therefore:

Now, angles 1 and 2 are alternate exterior angles, then:

Finally, angles 2 and 3 are consecutive interior angles, then:

Solving for angle 3, we get:

Answer:
Angle 1 is 68 degrees due to the corresponding angles theorem.
Angle 2 is 68 degrees due to the alternate exterior angles theorem.
Angle 3 is 112 degrees due to the consecutive angles theorem.
Examples:
Alternate exterior angles: angles A and B are alternate exterior angles.
Alternate interior angles: angles C and D are alternate interior angles: