SOLUTION: If I know the length of a cord of a circle and the distance from the center of the cord to the edge of the circle. How do I find the radius of the circle. Thanks. Jim

You can put this solution on YOUR website!
Lacking a graphics capability, I'll try to explain in words how to go about this solving this problem. Perhaps you can draw the diagram yourself from the description below:
Draw a circle. Then draw two radii separated by some angle (the size of the angle is not crucial to solving).
Let's call the radius, R.
Now draw the chord connecting the two ends of the radii.
Let's call this C (for chord).
Now draw a third radius that bisects the chord.
So now each half of the chord is length C/2
The known distance from the chord to the circumference of the circle can be x.
So, what we need is an equation that relates the radius, R, to the length of the chord, C, and the distance, x.
If your diagram is correct, it should show inside the circle, a triangle formed by the first two radii and the chord.
The third radius exactly bisects this triangle into two congruent right triangles.
The hypotenuse of the right triangle is just radius, R.
The base of the right triangle is just half the length of the chord or C/2.
The height of the right triangle is R - x.
Now we can use the Pythagorean theorem to solve the problem.

Now we need to solve for R.
Simplifying:

Subtracting R^2 from both sides, we get:

Adding 2Rx to both sides:

Dividing both sides by 2x:

This simplifies to:

Since you know the length of the chord, C, and the distance, x, you can find the radius, R.