 Manipulative 1: Reflection. Created with GeoGebra. 

A reflection is a geometric transformation. In a
reflection, a geometric object is 'flipped' across a
line. The line across which an object is reflected is called the
line of reflection or the
axis of reflection.
Manipulative 1 shows the reflection of an irregular pentagon across a line.
Click on the blue points in manipulative 1 and drag them to change the figure. Note
that the reflected figure is a mirror image of the original
figure. To see the construction of A' and B', click on the
check boxes.
Properties of Reflections
 An object and its reflection are symmetrical about the line of reflection.
 An object and its reflection are
congruent.
 An object and its reflection are
similar.
 If a reflected object is reflected again about the same line of reflection,
the resulting object is
coincidental
with the original object.
