Answer
The measure of p is 50 degrees.
Explanation
You can see that p is located in a triangle.
The interior angles of a triangle always add up to 180 degrees.
So, to solve this problem, you can find the other interior angles, then subtract those from 180 to find p.
The exterior angles are 140 and 90 degrees. To find the measure of the interior angles, you subtract them from 180, (because the exterior angles and interior angles add up to 180).
The measure of the interior angles are 40 and 90 degrees; 180-140=40 and 180-90=90.
Now you can subtract the measure of the two interior angles from 180 to find p; 180-40-90=50.