Geometry

Symmetry Rotation Translation Reflection

Symmetry

What is a line of symmetry? A line on which a figure can be folded so that both sides match.

To be a line of symmetry, the shape must have two halves that match exactly. When you trace a heart onto a piece of folded paper, and then cut it out, the two half hearts make a whole heart. The two halves are symmetrical.

Which of these flags have a line of symmetry? United States of America Canada No Maryland England No

What about these math symbols? Do they have symmetry? + - Yes Yes - x Yes Yes

How many lines of symmetry to these regular polygons have? 5 4 3 Do you see a pattern? 6 8

A B C D E FG H I J K L M N O P Q R S T U V W X Y Z You can look to see if your name has symmetrical letters in it too! A B C D E FG H I J K L M N O P Q R S T U V W X Y Z Infinite number

The action of turning a figure around a point or a vertex. Rotation (Turn) The action of turning a figure around a point or a vertex.

Rotation Click the triangle to see rotation Turning a figure around a point or a vertex Rotation

The action of sliding a figure in any direction. Translation (Slide) The action of sliding a figure in any direction.

Click the Octagon to see Translation. The act of sliding a figure in any direction.

The result of a figure flipped over a line. Reflection (flip) The result of a figure flipped over a line.

Reflection Click on this trapezoid to see reflection. The result of a figure flipped over a line.

Which shapes show reflection, translation, or rotation?

Parallel Two lines that are always the same distance apart.

Intersecting Where two lines crossover, and share some common point.

Perpendicular When two lines intersect at right angles.

Vertical A straight line that goes up and down.

Horizontal A straight line that goes side to side.