Stretching+and+Shrinking+10-11

__ Stretching and Shrinking __

Big Idea Many things in our world are mathematically similar and we can use this to understand and describe the world around us.

Essential Question # 1 - How can I make a drawn figure larger? 1.1 Stretching a Figure - Mathematical Reflections p.13 -

Essential Question # 2 - What is the same and what is different about “similar” figures? 2.1 Drawing Wumps - 2.2 Nosing Around - 2.3 Making Wump Hats - Mathematical Reflections p. 27 -



Essential Question # 3 - How can I use math to check if two figures are similar? 3.1 Identifying Similar Figures - 3.2 Building with Rep-tiles - 3.3 Subdividing to find Rep-tiles - Mathematical Reflections p.40 -

Essential Question # 4/5 - What types situations can I use my similarity ideas to solve? 4.1 Using Similarity to Solve a Mystery - 4.2 Scaling Up - 4.3 Making Copies - 4.4 Using Map Scales - Mathematical Reflections p.58 -

Essential Question # 4/5 - What types situations can I use my similarity ideas to solve? 5.1 Using Shadows to Find Heights - 5.2 Using Mirrors to Find Heights - 5.3 Using Similar Triangles to find Distances - Mathematical Reflections p. 74 -

Stretching and Shrinking Vocabulary
 * 1) angle measure
 * 2) compare
 * 3) congruent
 * 4) corresponds/corresponding
 * 5) diameter
 * 6) image
 * 7) parallel
 * 8) perpendicular
 * 9) ratio
 * 10) scale
 * 11) scale factor
 * 12) similar
 * 13) vertex

Notes:
 * 2.1 statements**

When I: Multiply x by a # > 1, the image gets wider, and stretches side ways by the scale factor. Multiply y by a # > 1, the image gets taller by the scale factor. Multiply x by 0<#<1, the image becomes thinner, slimmer and less wider by the scale factor. Multiply y by 0<#<1, the image becomes shorter When I multiply both x & y by the same numbers, the image changes its size and is similar by the scale factor. When I multiply both x & y by the different numbers, the image is not similar.


 * 2.3 statements**

When I: Add to x, the image is congruent, and moves to the right the number I added (addend), but doesn’t change its size. Add to y, the image is congruent, and moves to the up the number I added (addend), but doesn’t change its size. Subtract from x, the image is congruent, and moves to the left the number I added (addend), but doesn’t change its size. Subtract from y, the image is congruent, and moves to the down the number I added (addend), but doesn’t change its size.