due by the end of the day please help, 15
points

We have an inscribed angle here. Angle YXZ is an inscribed angle.
Angle YXZ can also be expressed as simply angle x but I will use angle YXZ.
Angle YXZ = (1/2)(arc YZ)
Angle YXZ = (1/2)(144°)
Angle YXZ = 72°
Done!