How to use this applet:
To use the applet, select a shape (Circle 1 is selected by default). For both circles, where the mouse is pressed is the centre and where the mouse is subsequently released is the edge of the radius. For the line, where the mouse is pressed is the first point and where the mouse is released is the second point. A line is automatically drawn between the points.
NOTE: What is shown is only a line segment. The actual line is infinitely long but obviously this cannot be shown!
Press the buttons to check the intersections or to clear the graph.
Notes on the maths used in the applet:
For overlapping circles, the principle used is that if the sum of the circles’ radii is greater than the distance between the centres (Distance is calculated using the square root of (x2 – x1)2 + (y2 – y1)2 formula), the circles overlap.
For overlapping lines and circles, the principle used is that if the perpendicular distance from the center of the circle to the line (Distance is calculated using the absolute value of (ax + by + c)/square root of (a2 + b2) formula where a, b and c are the coefficients of the line’s equation ax + by + c = 0 and x, y are the co-ordinates of the centre of the circle) is less than the radius of the circle, the line and circle overlap.
Other useful information:
Enjoy!
