WORKSHEET KEY 1 2 3 4 5 Yes

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WORKSHEET KEY 1) 2) 3) 4) 5) Yes No No (6, 6), (– 3,

WORKSHEET KEY 1) 2) 3) 4) 5) Yes No No (6, 6), (– 3, – 3), (0, 3) A’ (– 8, 8), B’ (4, 8), C’ (– 4, – 4) 3/6/2021 3: 10 AM 8) 7/13 9) 4 10) 1/3 11) C 12– 7: Tessellations 1

3/6/2021 3: 10 AM 12– 7: Tessellations 2

3/6/2021 3: 10 AM 12– 7: Tessellations 2

MONDAY FUN DAY 3/6/2021 3: 10 AM 12– 7: Tessellations 3

MONDAY FUN DAY 3/6/2021 3: 10 AM 12– 7: Tessellations 3

TESSELLATIONS Section 12– 7 Geometry Pre. AP, Revised © 2014 viet. dang@humble. k 12.

TESSELLATIONS Section 12– 7 Geometry Pre. AP, Revised © 2014 viet. dang@humble. k 12. tx. us 3/6/2021 3: 10 AM 12– 7: Tessellations 4

REVIEW A. Find the sum of the interior angle measures of each polygon. 1.

REVIEW A. Find the sum of the interior angle measures of each polygon. 1. Quadrilateral 2. Octagon 360° 1080° B. Find the interior angle measure of each regular polygon. 1. Square 90° 2. Pentagon 108° 3. Hexagon 120° 4. Octagon 135° 3/6/2021 3: 10 AM 12– 7: Tessellations 5

TESSELLATIONS A. A tessellation, or tiling, A Tessellation is a collection of shapes that

TESSELLATIONS A. A tessellation, or tiling, A Tessellation is a collection of shapes that fit together to cover a surface without overlapping or leaving gaps. B. Greek word, Tessella which means “four” C. Three regular shapes (all sides and angles) can be made to tessellations 1. Equilateral Triangles: 60° 2. Squares: 90° 3. Hexagons: 120° D. A semiregular tessellation is formed by two or more different regular polygons 3/6/2021 3: 10 AM 12– 7: Tessellations 6

VIDEO http: //www. youtube. com/watch? v=t. JYt. BF 6 gt 4 c 3/6/2021 3:

VIDEO http: //www. youtube. com/watch? v=t. JYt. BF 6 gt 4 c 3/6/2021 3: 10 AM 12– 7: Tessellations 7

REAL WORLD EXAMPLES 3/6/2021 3: 10 AM Brick Walls Floor Tiles Checkerboard s Honeycombs

REAL WORLD EXAMPLES 3/6/2021 3: 10 AM Brick Walls Floor Tiles Checkerboard s Honeycombs Textile Patterns Art 12– 7: Tessellations 8

REGULAR VS SEMIREGULAR TESSELLATION 3/6/2021 3: 10 AM 12– 7: Tessellations 9

REGULAR VS SEMIREGULAR TESSELLATION 3/6/2021 3: 10 AM 12– 7: Tessellations 9

REGULAR VS SEMIREGULAR TESSELLATION Regular Tessellations Semi-Regular Tessellations Symmetry in Tessellations 3/6/2021 3: 10

REGULAR VS SEMIREGULAR TESSELLATION Regular Tessellations Semi-Regular Tessellations Symmetry in Tessellations 3/6/2021 3: 10 AM 12– 7: Tessellations 10

STEPS A. Rotate the quadrilateral 180° about the midpoint of one side. B. Translate

STEPS A. Rotate the quadrilateral 180° about the midpoint of one side. B. Translate the resulting pair of triangles to make a row C. Translate the row of quadrilaterals to make a tessellation. 3/6/2021 3: 10 AM 12– 7: Tessellations 11

EXAMPLE 1 Copy the given figure and use it to create a tessellation. 3/6/2021

EXAMPLE 1 Copy the given figure and use it to create a tessellation. 3/6/2021 3: 10 AM 12– 7: Tessellations 12

EXAMPLE 2 Copy the given figure and use it to create a tessellation. 3/6/2021

EXAMPLE 2 Copy the given figure and use it to create a tessellation. 3/6/2021 3: 10 AM 12– 7: Tessellations 13

EXAMPLE 3 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM

EXAMPLE 3 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM 12– 7: Tessellations 14

EXAMPLE 4 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM

EXAMPLE 4 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM 12– 7: Tessellations 15

EXAMPLE 4 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM

EXAMPLE 4 Classify each tessellation as regular, semiregular, or neither. 3/6/2021 3: 10 AM 12– 7: Tessellations 16

YOUR TURN Classify each tessellation as regular, semiregular, or neither. Then, explain why. 3/6/2021

YOUR TURN Classify each tessellation as regular, semiregular, or neither. Then, explain why. 3/6/2021 3: 10 AM 12– 7: Tessellations 17

TYPES OF TESSELLATIONS A. B. C. D. Rotations Translations Reflection Glide Translation 3/6/2021 3:

TYPES OF TESSELLATIONS A. B. C. D. Rotations Translations Reflection Glide Translation 3/6/2021 3: 10 AM 12– 7: Tessellations 18

ROTATIONS A. To rotate an object means to turn it around. Every rotation has

ROTATIONS A. To rotate an object means to turn it around. Every rotation has a center and an angle. A tessellation possesses rotational symmetry if it can be rotated through some angle and remain unchanged. B. Examples of objects with rotational symmetry include automobile wheels, flowers, and kaleidoscope patterns. 3/6/2021 3: 10 AM 12– 7: Tessellations 19

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 20

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 20

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 21

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 21

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 22

ROTATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 22

TRANSLATIONS A. To translate an object means to move it without rotating or reflecting

TRANSLATIONS A. To translate an object means to move it without rotating or reflecting it. Every translation has a direction and a distance. A tessellation possesses translational symmetry if it can be translated (moved) by some distance and remain unchanged. B. A tessellation or pattern with translational symmetry is repeating, like a wallpaper or fabric pattern. 3/6/2021 3: 10 AM 12– 7: Tessellations 23

TRANSLATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 24

TRANSLATIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 24

REFLECTIONS TRANSLATIONS A. To reflect an object means to produce its mirror image. Every

REFLECTIONS TRANSLATIONS A. To reflect an object means to produce its mirror image. Every reflection has a mirror line. A tessellation possesses reflection symmetry if it can be mirrored about a line and remain unchanged. A reflection of an “R” is a backwards “R”. 3/6/2021 3: 10 AM 12– 7: Tessellations 25

REFLECTIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 26

REFLECTIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 26

GLIDE REFLECTIONS A. A glide reflection combines a reflection with a translation along the

GLIDE REFLECTIONS A. A glide reflection combines a reflection with a translation along the direction of the mirror line. Glide reflections are the only type of symmetry that involve more than one step. A tessellation possesses glide reflection symmetry if it can be translated by some distance and mirrored about a line and remain unchanged. B. A real world example is footsteps! 3/6/2021 3: 10 AM 12– 7: Tessellations 27

GLIDE REFLECTIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 28

GLIDE REFLECTIONS 3/6/2021 3: 10 AM 12– 7: Tessellations 28

ASSIGNMENT Worksheet 3/6/2021 3: 10 AM 12– 7: Tessellations 29

ASSIGNMENT Worksheet 3/6/2021 3: 10 AM 12– 7: Tessellations 29