Line p is parallel to side BC.
What is the measure of angle 1 in degrees?

In order to find the angle 1 in degrees we will use the concept of parallel and transversal line.
Now, we have been given that line p is parallel to the line BC and AB is transversal line.
Now angle ABC and angle 1 are alternate interior angles and they are equal.
Hence, we have
[tex]\angle 1 = \angle ABC\\ \angle 1 =73^{\circ}[/tex]
The measure of angle 1 is 73 degrees.