Lot set

${\displaystyle \alpha =\beta }$

The perpendicular theorem is a proposition of elementary geometry , which states the following:

Be in a Euclidean plane to two given straight line and from a given point of the solder and the two straights like , so agree with the directional angle between the perpendiculars and and the directional angle between the straight and consistent. The following applies: ${\displaystyle g_{1}}$ ${\displaystyle g_{2}}$ ${\displaystyle P}$ ${\displaystyle l_{1}}$ ${\displaystyle l_{2}}$ ${\displaystyle l_{1}}$ ${\displaystyle l_{2}}$ ${\displaystyle g_{1}}$ ${\displaystyle g_{2}}$ ${\displaystyle \angle (l_{1},l_{2})=\angle (g_{1},g_{2})}$

The same applies to the three-dimensional visual space : The perpendiculars on two given levels form the same angle as the levels themselves.

literature

• Hermann Athen and Jörn Bruhn [eds.]: Lexicon of school mathematics and related areas. Volume 3. L - R . Aulis Verlag Deubner & CO KG, Cologne 1977, ISBN 3-7614-0242-2 .

Individual evidence

1. ^ Lexicon of school mathematics . tape 3 , p. 608 .