How to find the exact center of a circle

Today I wanted to share a quick geometry trick which you may find handy if you are working on a project that involves a circle shape: how to find the center of a circle.

The principle of it is based on the following theorem:

“A tangent always forms a right angle with the circle’s radius.”

Sounds pretty geeky right? I know… when the subject is math or computers I tend to get a bit geeky. But still I am not even close to Greg’s level when the subject is wine, music, or science (especially stuff related to outer space.) You may guess what fun parents we are 😀 … anyway, let’s get back to the tutorial.

Draw a line on a circle as shown below. Don’t worry about where the line is, because any line that crosses a circle is ultimately parallel to a tangent line. But the only important thing is that you draw your line to measure a simple number that is dividable by 2 as it will ease your job in next step.

Find the middle of that line and mark it. My line was exactly 8 inches, so I marked the middle at 4 inches.

From that middle point, draw a right angle line long enough to pass what you deem the middle of the circle.

Now do the same steps once again on another side of the circle.

The point where your 2 right angle lines cross each other is the center of that circle.

It was pretty simple, right?

I hope you find this information useful when working on projects like tiered stands, clocks, round side tables, et cetera.

Handan, xo