C#/VS2005 - The degree and where the line is to the edge of the circle do not seem to match

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        //set the degree variable, default 0
        int degrees;
        // First snippet
        //create a random type object that will hold our randomly generated number/degree
        Random createRandom = new Random();
        int dialPosition, dialPosition2, dialPosition3, dialPosition4, dialPosition5;
 
        public Form1()
        {
            InitializeComponent();
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
            newReads();
        }
 
        //drawLine method that will create conversions of degrees to radians
        private void drawLine(Bitmap draw)
        {
            //set the length that the lines will be drawn to
            int length;
            //create points for determining center of the circles
            float x0, y0, x, y;
 
            // Set x0 and y0 to your own numbers. Points to draw our radial line from
            x0 = pictureBox1.Width / 2;
            y0 = pictureBox1.Height / 2;
            
            if (x0 < y0)
                length = (int)x0 - 3;
            else
                length = (int)y0 - 3;
 
            x = x0 + (float)(Math.Cos(((double)degrees / 360) * 2 * Math.PI) * length);
            y = y0 + (float)(Math.Sin(((double)degrees / 360) * 2 * Math.PI) * length);
 
            //create a graphics object that will allow us to create the pen object
            Graphics g;
            //create our pen to draw with
            Pen myPen = new Pen(Color.Black, 2);
 
            g = Graphics.FromImage(draw);
            //draw our circle
            g.DrawEllipse(new Pen(Color.Black, 1), x0 - length, y0 - length, length * 2, length * 2);
            //draw our line using the points from earlier calculations and assignments
            g.DrawLine(myPen, x0, y0, x, y);
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            listBox1.SelectedIndex = -1;
            pictureBox1.BackColor = Color.White;
            listBox5.SelectedIndex = -1;
            pictureBox5.BackColor = Color.White;
            newReads();
        }
 
        private void newReads()
        {
            //generate a new degree for the dial when button click
            degrees = createRandom.Next(0, 359);
            dialPosition = degrees;
            label1.Text = dialPosition.ToString();
            Bitmap draw = new Bitmap(pictureBox1.Width,
                pictureBox1.Height);
            drawLine(draw);
            pictureBox1.Image = draw;
 
            //generate a new degree for the dial when button click
            degrees = createRandom.Next(0, 359);
            dialPosition2 = degrees;
            Bitmap draw2 = new Bitmap(pictureBox2.Width,
                pictureBox2.Height);
            drawLine(draw2);
            pictureBox2.Image = draw2;
 
            //generate a new degree for the dial when button click
            degrees = createRandom.Next(0, 359);
            dialPosition3 = degrees;
            Bitmap draw3 = new Bitmap(pictureBox3.Width,
                pictureBox3.Height);
            drawLine(draw3);
            pictureBox3.Image = draw3;
 
            //generate a new degree for the dial when button click
            degrees = createRandom.Next(0, 359);
            dialPosition4 = degrees;
            Bitmap draw4 = new Bitmap(pictureBox4.Width,
                pictureBox4.Height);
            drawLine(draw4);
            pictureBox4.Image = draw4;
 
            //generate a new degree for the dial when button click
            degrees = createRandom.Next(0, 359);
            dialPosition5 = degrees;
            label5.Text = dialPosition5.ToString();
            Bitmap draw5 = new Bitmap(pictureBox5.Width,
                pictureBox5.Height);
            drawLine(draw5);
            pictureBox5.Image = draw5;
        }
 
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (listBox1.SelectedIndex == 1)
            {
                if (dialPosition > 34 & dialPosition < 72)
                {
                    pictureBox1.BackColor = Color.Green;
                }
                else { pictureBox1.BackColor = Color.Red; }
            }
        }
 
        private void listBox5_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (listBox5.SelectedIndex == 1)
            {
                if (dialPosition5 > 34 & dialPosition5 < 72)
                {
                    pictureBox5.BackColor = Color.Green;
                }
                else { pictureBox5.BackColor = Color.Red; }
            }
        }
 
    }
}

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