How to Find the Center of a Circle - Method 2

http://www.alexpleasehelp.com/online/problems/center2

This is another way to find the center of a circle. With this method all that is required is a straight edge and a piece of paper (as long as the corners of the paper are 90 degrees.

The circle you have must be at least 180 degree complete for this method to work, ideally it should be at least 270 degrees complete so that the intersection of the two diameters can be seen more easily.

Category:

Howto & Style

Tags:

• math
• geometry
• circle
• center
• find
• physics
• drafting

[peg2003]

So all you need really is something with a right-angle on it - like a set square? As long as its edges are longer than the diameter of the circle, you don't need to have the "right" size of paper. Or you can use another piece of paper. Is this correct? Thanks for the nice video. :)

[AlexPleaseHelpDotCom]

@peg2003 That's correct you don't need to use the sheet of paper you drew the circle on. It can be anything that has a 90 degree corner.

[rigimp]

does this circle have to be in the dead center of the page for this to work?

[AlexPleaseHelpDotCom]

@rigimp No the circle can be anywhere. And technically you dont even need a whole circle.

If you're using a compass and straight edge the only thing you have to have is space to draw the lines and curves.

[Dudeeoman]

This is cool, you definitely made my method look more legitimate. What program did you use to draw these figures?

[AlexPleaseHelpDotCom]

I use a program called Geogebra. It's free and awesome.

[telosfd]

I like your Greeks!!!!!!!!!!!

Ok i like it .

[ReverendNillerz]

The previous method was less than illuminating to say the least. This trick is much better. Thank you for this video.

[hotwheels770]

actualy if you have a ruler you only have to fold it once and then devide the length of the diameter of the circle by 2 and then you have the center

[jesper92]

... if you have paper you can just fold the circle in half twice to find the center and measure the radius

[mrjost55]

wow that's awesome, quick and easy!