3. Let’s do a little review work before discussing similar figures.
4.
5. Read IT Correctly spell and pronounce the term Write IT Write the definition of the term in your own words Draw IT Represent the term through examples and visuals
21. The value of the missing factor is 1.5. 18 12 15 12 10 8 1.5 =
22. When changing the size of a figure, will the angles of the figure also change? ? ? ? 70 70 40
23. Nope! Remember, the sum of all 3 angles in a triangle MUST add to 180 degrees. If the size of the angles were increased, the sum would exceed 180 degrees. 70 70 40 70 70 40
24. We can verify this fact by placing the smaller triangle inside the larger triangle. 70 70 40 70 70 40
25. 70 70 70 70 40 The 40 degree angles are congruent.
26. 70 70 70 70 70 40 40 The 70 degree angles are congruent.
27. 70 70 70 70 70 40 4 The other 70 degree angles are congruent.
56. Scale factor = new value old value . 8cm 12cm 5cm 7.5cm New value = Old value New value = Old value 12 = 3 or 1.5 8 2 Can you see the relationship between the two scale factors? 8 = 2 12 3 Scale factor? Scale factor?
57. Using scale factor 9cm a Enlarge with scale factor 3 b 15cm a = 9 x 3 = 27cm SF = new/old = 9/27 = ⅓ What will the scale factor be? b = 15 x ⅓ = 15 ÷ 3 = 5cm OR reciprocal of 3 = ⅓