How do I find points on a circle?

[celsius]

I am having trouble with this one - I need to calculate the points of a circle. For example: If you wanted to make a clock (the kind with hands) and have a line spin around like the hands, I need to calculate the outer points to do that. Can anyone help? thanks.

http://www.angelfire.com/or/cam13

[John]

For a clock in particular, have a look at:

http://visualbasic.about.com/compute/visualbasic/library/weekly/aa112399a.htm

Some of the concepts can be used to determine the points on a circle.

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John Percival
Editor, VB-World.net
john@vb-world.net

[celsius]

Thanks for the help, but I forgot to add one thing; I am making a look-alike "radar" and it beeps when the line passes over the dot. Any suggestions on how to detect when it passes? Thanks

Your point (on a circle) should form some angle with the axis point of your radar sweep and the horizontal line going through (say 9 o'clock to the axis point to 3 o'clock--from left to right). If you decide to call 12 o'clock to be NORTH equal to 0 degrees, then 1 o'clock is 30 degrees, 2 o'clock is 60 degrees etc, until you go back to 12 equals 360 degrees which is the same as 0 degrees.
You calculate the angle of the (point on the circle) using this reference; then as the radar sweeps around, you can say
If RadarSweepAngle = PointAngle Then Beep

I trust that you know about Polar and Cartesian Coordinates, so the rest is trivial.

Merry Christmas