Year 5

Reflection

Flip of a figure about an axis d that is perpendicular to a given direction. The axis d is called the line of reflection.
Symmetry about an axis d perpendicular to a given direction. The axis d is called the line of reflection.
  • The term "reflection" is a synonym for orthogonal symmetry.
  • Frieze patterns and tessellations can be created by applying reflections.

Notation

A reflection is often denoted by the letter "r". A subscript may also be added to represent its axis. For example : rd refers to a reflection r across an axis d.

Properties

The invariants under a reflection in a plane are as follows: A reflection also preserves:
  • the perimeter and area of plane figures;
  • the measures of angles.
The orientation of a plane is not preserved under a reflection, since a reflection is a flip that reverses the orientation of the plane.

See also :

Netmath, the educational platform where students have fun learning!

Try our activities