NEED HELP FAST

Hi I am useing the following code to draw a circle

            this.TransparencyKey = Color.WhiteSmoke;
            this.BackColor = Color.WhiteSmoke;
            this.Refresh();
            Graphics g = this.CreateGraphics();
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.Default;        
            g.DrawArc(new Pen(Brushes.Blue, 6f), 5, 5, 700, 700, 0, 90);
            g.DrawArc(new Pen(Brushes.Red, 6f), 5, 5, 700, 700, 90, 90);
            g.DrawArc(new Pen(Brushes.Yellow, 6f), 5, 5, 700, 700, 180, 90);
           g.DrawArc(new Pen(Brushes.Green, 6f), 5, 5, 700, 700, 270, 90);

but i am tring to have the following colors in 90' segments starting with 0' if 0' was due north... all the way around the circle....

green 315 - 45
blue 45 - 135
red 135 - 225
yellow 225-315