Answer:
s = 7 degrees
Explanation:
All the angles have to add up to 180, so take 180 - 90 - 54 (the angles you know), and set them equal to 4s + 8. You get 36 = 4s + 8, subtract 8 from both sides, divide by 4, and you get that s = 7 degrees
Hopefully this helps! Let me know if you have any questions