corresponding angles in transversal cutting
Its converse theorem is also valid in Euclidean geometry:
If two parallel lines ( and ) are cut by a transversal (), then each pair of corresponding angles (e.g. and ) are congruent.
The angle in both theorems may be replaced with its vertical angle . The angles and are called alternate interior angles of each other.
Two lines that are perpendicular to the same line are parallel to each other.
If a line is perpendicular to one of two parallel lines, then it is also perpendicular to the other.
If the left sides of two convex angles are parallel (or alternatively perpendicular) as well as their right sides, then the angles are congruent.
- 1 K. Väisälä: Geometria. Kolmas painos. Werner Söderström Osakeyhtiö, Porvoo ja Helsinki (1971).
|Title||corresponding angles in transversal cutting|
|Date of creation||2013-03-22 17:15:12|
|Last modified on||2013-03-22 17:15:12|
|Last modified by||Wkbj79 (1863)|
|Defines||alternate interior angle|