Consider a rotation through an angle either
\(\alpha = 180^{\circ }\) or
\(\alpha = 360^{\circ }\). How
many lines which are mapped into itself exists for this rotation?
How many points of symmetry there exist for a rhombus? A rhombus -- opposite sides are parallel and all sides have equal length. (A point is a point of
symmetry of the rhombus if the reflection through this point maps the rhombus into
itself.)
Which of the following answers contains three letters with point symmetry? (A letter
has a point of symmetry if there exists a point, such that the reflection through this
point maps the letter into itself.)
Given a translation of a plane, find the property of a line obtained by translating a line
\(r\). The
line \(r\) is
neither parallel not perpendicular to the translation vector.
The resulting line is parallel to the line
\(r\).
The resulting line is perpendicular to the translation vector.
The resulting line is perpendicular to the line
\(r\).
The resulting line is the line \(r\).
(The line \(r\)
is mapped into itself.)