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- 2D Shapes and Planes

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Get Started Now- Intro Lesson: a7:20
- Intro Lesson: b7:20
- Intro Lesson: c8:13
- Intro Lesson: d6:20
- Lesson: 1a2:46
- Lesson: 1b4:22
- Lesson: 1c2:23
- Lesson: 2a2:05
- Lesson: 2b3:00
- Lesson: 2c2:52
- Lesson: 3a2:12
- Lesson: 3b2:05
- Lesson: 3c2:21
- Lesson: 3d2:08
- Lesson: 4a1:50
- Lesson: 4b2:00
- Lesson: 4c2:21
- Lesson: 5a4:33
- Lesson: 5b5:48
- Lesson: 6a4:00
- Lesson: 6b2:11
- Lesson: 6c2:56

In this lesson, we will learn:

- How to draw reflections on a grid with vertical, horizontal, or diagonal mirror lines
- How to find order of rotational symmetry for shapes with multiple symmetry lines
- How to rotate shapes around a point 90°, 180°, 270°, and 360° clockwise or counter-clockwise

- For
, a__line symmetry__**mirror test**check ifhalves match*reflected*

- When drawing
**reflections**of shapes, a**grid**and a**line of symmetry**are used - For reflections, the line of symmetry will be called the “
**mirror line**” instead - There can be
**vertical, horizontal**, and**diagonal**mirror lines

- Choose some exact points of the
*original*shape on the grid - To draw the
*reflection*of these points, they must be the__same distance__away from the mirror line as the original points (**perpendicularly**)

- Another type of symmetry is called
__rotational symmetry__ - If a shape has
lines of symmetry: when you spin it around in a*multiple**full circle*(360°), it will look exactly the same more than once

Ex. a triangle has 3 lines of symmetry; rotating a full circle, it matches the original 3 times

- Therefore, the
**order of rotational symmetry**for this regular triangle is = 3

- When
**rotating shapes**, the shape will be spun around a point (usually the middle): - either
**clockwise**or**counter-clockwise** - To one of 4 main
**rotation angles**: 90°, 180°, 270°, and 360°

Ex. Rotate the shape of the letter “P” clockwise 90°, 180°, and 270° around the point

- IntroductionIntroduction to Reflections and Rotations of Shapes:a)Drawing reflections (mirror images) on a gridb)What is rotational symmetry?c)Rotating shapes around a point (four main rotational angles)d)Special example of reflecting and rotating a shape
- 1.
**Drawing reflections on a grid - 1**

Draw the mirror image after the shape is reflected across the mirror line (dotted line).a)b)c) - 2.
**Drawing reflections on a grid - 2**

Draw the reflections of both the lines and the points across the mirror line (dotted line).a)b)c) - 3.
**Rotational symmetry**

Does the picture have rotational symmetry? Yes or No.a)b)c)d) - 4.
**Order of rotational symmetry**

What is the order of rotational symmetry?- How many times does the shape look the same in one rotation?

a)b)c) - 5.
**Rotating shapes 90°, 180°, 270° or 360°**

Draw what it will look like if you rotate the shape:a)- 90° CW
- 90° CCW
- 180° CW

b)- 270° CW
- 180° CCW
- 360° CW

- 6.
**Recognizing reflections and rotations of shapes**

Circle the pairs that are correct.a)Which pairs are possible rotations of each other?b)Which pairs are possible reflections of each other?c)Which pairs have the line of reflection drawn properly?