Hello, thank you for taking the time to post your question!
The complement of an angle is 90 – x and the supplement of an angle is 180 – x … since it’s saying that the measure of the supplement is four times that of its complement we can set up the algebraic equation
Supplement = 4 * Complement
(180 – x) = 4(90 – x)
From there then it’s just a matter of solving for the value of “x” algebraically
180 – x = 360 – 4x
3x = 180
x = 60
so the angle that it’s after here is 60 degrees
I hope that helps get you moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)