Instruction: Construct an angle of 60° with the given side.
Goal: 3L 3E
Available tools:
- Move
- Point
- Line
- Circle
- Intersect
Pack: Alpha
Next level: 1.2
3L 3E solution
Let A be the initial point of the given ray.
- Construct a circle C1 with center A and an arbitrary radius, intersecting the ray at B
- Construct the circle C2 with center B and radius AB, intersecting circle C1 at C and D
- Construct line AC
2V solution
- Construct line AD
Explanation
All internal angles of an equilateral triangle are 60°, so you just need to construct the two sides of an equilateral triangle adjacent to vertex A. The two circles ensure that AB=AC=BC and AB=AD=BD and so ABC and ABD are equilateral and angles CAB and DAB are 60°.