Answer:
x = 67.5°
Explanation:
Angles around a point add up to 360°. This means that 3x + x + 90 = 360°. This can be simplified to 4x + 90 = 360°. Now, subtract 90 from both sides → 4x = 270°. Both sides can be divided by 4 to get x = 67.5°.
Hope this helps!