Ortsbogen theorem

Ortsbogen theorem

In geometry, for any line segment AB and angle θ < π, the locus of points C on one side of line AB such that angle ACB equals θ is an arc of a circle. Points outside this arc form sharper angles than θ, while points within this arc form wider angles.[1]

In the Swiss school curriculum this arc is known as an "Ortsbogen" and the theorem that the locus has this shape is known as the Ortsbogen theorem.[citation needed]

References

  1. ^ Euclid's Elements, book III, theorem 21.