How to make an equilateral triangle inside a circle?

Geometric construction of an equilateral consists of drawing a diameter of a circle OP_O and then constructing its perpendicular bisector P_3OB.

Bisect OB in point D, and extend the line P_1P_2 through D.

The resulting figure P_1P_2P_3 is then an equilateral triangle.

Thanks!

interesting.

in CAD, i would probably draw the triangle first, and then establish the radius for the circle...

That can be but in CAD I always design my geometric figures starting with the circle they are inserted in..

hey, it's rare finding someone else on here that uses CAD!

drawing the circle first can work against you if you're putting text in it.

this happens all the time --

you start out with a circle big enough for one digit, but later on in the project it increases to double-digits.

so, you either have to make the double-digits really narrow, or re-size the circle to fit the double-digit text at normal width...

See? The world is full of happenstances, serendipity even..

A different approach would be to draw the circle, lay out six equidistant points on the circumference, and using every other point as the apex of your triangle.

The length of the chord between each two of the six points is exactly the same as the radius, and if you used dividers to scribe the circle, they are properly set to lay out the six points.

Indeed Roger but it's only another method to achieve the result.

I can provide a few more but I find the first one easier than any other.

Thanks for reply