Answer:
Well supplementary means that both the angles add up to 180
We know that the measure of angle 3 is 13 degrees.
The measure of angle 4 is unknown
And the total of angles 3 and 4 are 180.
So you can make an equation
13 + x = 180
Solve for x
x= 167
Measure of angle 4 is 167
m< 4 = 167 degrees