perfect triangle inside a circle?

Question

How would I make an exactly evenly-sided triange inside of a circle and in which the three points of the triangle meet the line of the circle?

Answer 1

Draw a circle with compasses, keep them in the same position.
Now put the needle point of the compasses somewhere on the circle and draw a tiny bit of circle crossing the circle you just made, do that at both points where your 'new circle' will cross the original one. Now leave the drawing point of the compasses on the circle and swing the needle point around till it meets the circle again. In this position also draw both crossings.
You should now have three places marked on your circle, you can repeat the swing around the needle end and repeat till all three places are double marked.

If you have a printed circle, measure its diameter, half that size and use that as distance for the legs of the compasses.
If you do not have compasses, you can try to do the same using a ruler, but work real accurate and double mark all crossings.

Answer 2

I think this method would work. If you know the circumference of the circle divide it by three and those points would be the points of the triangle. Simply connect these points to form the triangle. For example, if the circumference of the circle is nine inches and you divide it by three there would be a point of the triangle every three inches on the circle. Connecting these points would give a triangle with three equal sides.

Answer 3

No, they will be slightly too big to fit. I found out by drwing the 4 circles in MS Word as autoshapes then resizing them to the appropriate dimensions. If the big circle was 135 mm they would just fit. A 136 mm diameter circle would fit the 3 bulbs easily.

Answer 4

Follow Willeke's instructions - it's called in English 'a pair of compasses', and not only will you be able to make an equilateral triangle, but hexagons - exciting.