1. Skyler Cornaby and Lyndon Crouch 13-4 SIMILAR AND CONGRUENT SOLIDS

2.  Identify congruent or similar solids  State the properties of similar solids

3. Definitions of similar and congruent Volume formulas for solids Scale factor Proportions NEED TO KNOW

4. Key Concept  Two solids are congruent if  The corresponding angles are congruent  The corresponding edges are congruent  The corresponding faces are congruent  The volumes are equal

5. E XAMPLE #1 Corresponding angles congruent Corresponding edges congruent Corresponding faces congruent Volumes equal 2 2 2 2 2 2

6. * Lyndon is buying a new cage for his hedgehog and he want to buy a cage similar to his original cage. The smaller cage is 10in.X7in.X6in. The larger cage is 20in.X14in.X15in. Are the cages similar?

7. * Length ratio-10:20 or 1:2 * Width ratio-7:14 or 1:2 * Height ratio-6:15 or 2:5 * The cages are not similar because not all the dimensional ratios are the same.

8.  If two solids are similar with a scale factor of a:b then the surface area have a ratio of a 2 :b 2, and the volumes, have a ratio of a 3 :b 3. Theorem 13.1 Scale factor 3:2 Ratio of surface areas 3 2 :2 2 or 9:4 Ratio of volumes 3 3 :2 3 or 27:8 10 8 12 15

9. Example #3 These two cylinders are similar. Using theorem 13.1 solve for the volume of the larger cylinder. 6 14 7

10. Example #3 cont’d

11.  Joey is trying to decide if his baseball and his basketball are similar. If his baseball has a radius of 1.45 in. and his basketball has a radius of 4.7 in. Are they similar?

12. 

13. Assignment O Pg. 711 11-26, 36-39