iOS drawing circle Path for percent state -

i try draw circle given percent value (like if have 25% draw quarter of circle). @ moment im able draw full circle within view. ideas problem?

code atm:

- (uibezierpath *)makecircleatlocation:(cgpoint)location radius:(cgfloat)radius {     self.circlecenter = location;     self.circleradius = radius;      uibezierpath *path = [uibezierpath bezierpath];     [path addarcwithcenter:self.circlecenter                     radius:self.circleradius                 startangle:0.0                   endangle:m_pi * 2.0                  clockwise:yes];       return path; }  - (void)drawcircleforlocation{     cgpoint location = cgpointzero;     location.x = self.frame.size.width/2;     location.y = self.frame.size.height/2;      cashapelayer *shapelayer = [cashapelayer layer];     shapelayer.path = [[self makecircleatlocation:location radius:9] cgpath];     shapelayer.strokecolor = [[uicolor whitecolor] cgcolor];     shapelayer.fillcolor = nil;     shapelayer.linewidth = 1.5;      [self.layer addsublayer:shapelayer]; } 

2 pi rad = 360° = full circle. 25% of circle = 2 pi * 25%

  - (uibezierpath *)makecircleatlocation:(cgpoint)location radius:(cgfloat)radius percent:(cgfloat)percent     {         self.circlecenter = location;  //????         self.circleradius = radius;    //????          uibezierpath *path = [uibezierpath bezierpath];         [path addarcwithcenter:location                         radius:radius                     startangle:0.0                       endangle:((m_pi * 2.0) * percent)                      clockwise:yes];          [path addlinetopoint:location];         [path closepath];         return path;     }