Question

Here is a straightedge and compass construction. Use a straightedge to draw an equilateral triangle on the figure. Explain how you know the triangle is equilateral.

Answer 1

We need to draw an equilateral triangle in this figure.

An equilateral triangle has sides of equal length. So to draw that in our figure we need to make sure that the sides of the triangle are all equal.

We can draw the following equilateral triangle:

We know this is an equilateral triangle because each side is a diameter of a circle. And for a straightedge all of the circles must have the same diameter: