1. Quick Start Expectations 1.Fill in planner and HWRS HW: p. 90, #1 (Hint: compare each one to all the others.) 2.Get a signature on HWRS 3.On desk: math journal, calculator, textbook, HWRS, pencil, pen 4.Warm Up: Read SS p. 80-81

3. SS p. 80

5. Original Ratios describe and compare shapes. The rectangle around the original figure is about 10 cm tall and 8 cm wide The ratio of height (10) to width (8) is 10 to 8 10 cm 8 cm Write in your journal:

6. Original 8 10 5 3 8 3 4 6 10 to 8 8 to 3 3 to 6 5 to 4

7. Can you find any ratios that are equal (equivalent)? Write in your journal: 10 to 8 and 5 to 4 are equivalent ratios You can express equivalent ratios with equations. A proportion is an equation of two equivalent ratios. Write in your journal:

8. Journal:11/24/14 Inv. 4: Ratios Ratios describe and compare shapes. The ratio of height (10) to width (8) is 10 to 8 10 to 8 and 5 to 4 are equivalent ratios E T Add to your journal: What information does the ratio give you?

10. A, B, and C are similar! 6 x 1.5 =9 10 x 1.5 = 15 SF for B to C is 1.5 20 x.75 =15 12 x.75 = 9 SF for A to C is.75 6 x 2 =12 10 x 2 = 20 SF for B to A is 2 6 x 1 =6 10 x 2 = 20 SF for B to D is NOT CONSISTENT IF “D” IS NOT SIMILAR TO “B”, IT ISN’T SIMILAR TO “A” OR “C” Open your book to p. 82

11. Short Long Similar rectangles have the SAME ratio! Non-similar rectangles have different ratios!

12. Scale Factor: B to A = 2 B to C = 1.5 C to A = This tells you how many times as great each side length and perimeter are

16. Scale Factor: B to A = 2 B to C = 1.5 C to A = Ratio of short side to long side Similar figures have a constant scale factor and their ratios of corresponding side lengths will be equivalent. The scale factor gives the amount of stretching (or shrinking) from the original figure to the image. The ratio of adjacent side lengths within a figure gives an indication of the shape of the original figure (and image), since it compares measures within one figure.

17. HW: p. 90, #1 (Hint: compare each one to all the others.)