Method 1: Simply plot 2 points on the xAxis. Then use Pythagorean Theorem to determine coordinates of 3rd vertex on zAxis.
Method 2: Use the REGULAR POLYGON tool to build directly on gray coordinate plane. Then rotate everything 90 degrees about the xAxis.
Method 3: Compass and straightedge constructions in MIDAIR? Absolutely! Here, we simply use the CIRCLE WITH CENTER THROUGH POINT tool twice. Note how we need to specify an axis of the circle as well (since we are in 3D).
Method 4: Use the ROTATE tool to rotate one point on the xAxis 60 degrees about the other point.