Constructing `120^@` using a compass
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Which of the following help to construct `120^@` angle using a compass?
- construct `60^@` on top of another `60^@` angle. Both together form `120^@`
- construct `60^@` on top of another `60^@` angle. Both together form `120^@`
- `120^@` angle cannot be constructed using a compass
The answer is "construct `60^@` on top of another `60^@` angle. Both together form `120^@`"
Constructing `60^@` angle twice-over to construct `120^@`
• With an arbitrary distance-measure on compass, mark point `P` from point `A` on line `bar(AB)`.
• With the same distance measure on compass, construct two arcs from points `A` and `P`. The arcs cut at point `Q`. `bar(AQ)` makes `60^@` with the `bar(AP)`.
• With the same distance measure on compass, construct two arcs from points `A` and `Q`. The arcs cut at point `R`. `bar(AR)` makes `120^@` with the `bar(AP)`. The angle `120^@` is constructed as `/_PAR`.
Constructing `120^@` angle using a Compass : Construct an equilateral triangle and another equilateral triangle on the side of the constructed one.