Transformations

These are Transformations:

Rotation rotation 2d Turn!
Reflection reflection on graph Flip!
Translation translation on graph Slide!

right arrow After any of those transformations (turn, flip or slide), the shape still has the same size, area, angles and line lengths.

Resizing

The other important Transformation is Resizing (also called dilation, contraction, compression, enlargement or even expansion). The shape becomes bigger or smaller:

Resizing resize on graph

Congruent or Similar

When one shape can become another using only Turns, Flips and/or Slides, then the two shapes are Congruent.

Two shapes are Similar when we need to Resize for one shape to become another (we may also Turn, Flip and/or Slide).

So, when one shape can become another using transformation, the two shapes might be Congruent or just Similar

When one shape becomes another ...       The shapes are ...
... using only Rotate, Reflect and/or Translate    right arrow  

Congruent

... using a Resize (may also Rotate, Reflect
and/or Translate)
  right arrow  

Similar