Constructing an equilateral triangle inscribed in a circle

This is the step-by-step, printable version. If you PRINT this page, any ads will not be printed.

See also the animated version.

After doing this Your work should look like this
We start with the given circle, center O.

Note: If you are not given the center, you can find it using the method shown in Finding the center of a circle with compass and straightedge.
1.  Mark a point anywhere on the circle.
2.  Set the compasses on this point and set the width of the compasses to the center of the circle. The compasses are now set to the radius of the circle
3.  Make an arc across the circle.
4.  Move the compasses to this new point and draw another arc.
5.  Continue in this way until you have six points in total.
6.   Label every other point B,D and F
7.   Draw the lines BD, DF, FB
8.   Done. The lines BD, DF, FB form an equilateral triangle inscribed in the given circle.
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Other constructions pages on this site




Right triangles

Triangle Centers

Circles, Arcs and Ellipses


Non-Euclidean constructions