1 Shagore

Lesson 2 Homework Practice Reflections


Reflections are everywhere ... in mirrors, glass, and here in a lake.
... what do you notice ?

Every point is the same distance from the central line !

... and ...

The reflection has the same size as the original image

The central line is called the Mirror Line ...



Can A Mirror Line Be Vertical?

Here my dog "Flame" shows a
Vertical Mirror Line (with a bit of photo magic)

In fact Mirror Lines can be in any direction.
Imagine turning the top image in different directions:



A reflection is a flip over a line

You can try reflecting some shapes about different mirror lines here:

How Do I Do It Myself?

 Just approach it step-by-step. For each corner of the shape:
 1. Measure from the point to the mirror line (must hit the mirror line at a right angle)2. Measure the same distance again on the other side and place a dot.3. Then connect the new dots up!


It is common to label each corner with letters, and to use a little dash (called a Prime) to mark each corner of the reflected image.

Here the original is ABC and the reflected image is A'B'C'

Some Tricks


When the mirror line is the x-axis
we change each (x,y) into (x,−y)



When the mirror line is the y-axis
we change each (x,y) into (−x,y)

Fold the Paper

And when all else fails, just fold the sheet of paper along the mirror line and then hold it up to the light !



Reflection SymmetryTransformationsRotationTranslationGeometry Index

Вирусы, - сказал он, вытирая рукой пот со лба, - имеют привычку размножаться. Клонировать самих. Они глупы и тщеславны, это двоичные самовлюбленные существа. Они плодятся быстрее кроликов.

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