FYI:
Spawn point - (x,y)
where:
x = CenterX + RADIUS * cos(YourAngle)
y = CenterY + RADIUS * sin(YourAngle)
CenterX, CenterY - center of your circle
RADIUS - circle radius
YourAngle - angle you want from 0 to 359
I think korbaach's solution is better (imo)