12.1.4 Compositions of Transformations Flashcards
composition of transformations
one transformation followed by another
glide transformation
the composition of a translation and a reflection across a line parallel to the translation vector
Theorem
composition of two isometries is an isometry
Theorem
The composition of two reflections across two parallel lines is equivalent to a translation.
• The translation vector is perpendicular to the lines.
• The length of the translation vector is twice the distance between the lines.
The composition of two reflections across two intersecting lines is equivalent to a rotation.
• The center of rotation is the intersection of the lines.
• The angle of rotation is twice the measure of the angle formed by the lines.
Theorem
Any translation or rotation is equivalent to a composition of two reflections