How to Find the Centre of a Circle 162p1j

The POSH way 3q2m5s

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Draw a chord anywhere across your circle (marked in yellow on the picture) Construct the perpendicular bisector (marked in blue on the picture). Draw another chord and do the same thing. Where the bisectors cross will be the centre. 4c2k3e

The USING A BOOK way 146j

1/ Get a circle		2/ Get a book that's at least as big as the circle. (If you haven't got a book you can use a rectanglular piece of paper).		3/ Put one corner of the book on the edge of the circle (See "C") Mark where the two edges of the book cross the circle (See "X" and "X")
4/ Remove the book and the marks with a straight line. This will be a diameter of the circle		5/ Do it again to get another diameter.		6/ Where the diameters cross is the centre.

This works thanks to the fact that the angle in a semi-circle is always a right angle. There's more of this stuff in Murderous Maths Main Index Page 5c4e17