Similarity 7 2 Review 1 If QRS ZYX
- Slides: 13
Similarity 7. 2
Review 1. If ΔQRS ΔZYX, identify the pairs of congruent angles and the pairs of congruent sides. Solve each proportion. (hint: cross multiply) 2. 3.
• Similar (~) Vocabulary – exactly the same shape not necessarily the same size • Similar Polygons – two polygons whose corresponding angles are congruent and corresponding sides are proportional. • Similarity Ratio – ratio of the lengths of corresponding sides • Ratio can be written: • a: b • a/b • a to b
Match the similar figures. 1. a. b. c. 2. c. a. b.
Checking for Similarity • In order to be similar, you must check for: – all corresponding angles congruent – all corresponding sides are proportional (meaning the ratios of each pair of matching sides is the same) – This ratio is the Similarity Ratio – You can then write a Similarity Statement: ∆ABC ~ ∆XYZ (order matters)
Describing similar polygons 1. Identify the pairs of congruent angles and corresponding sides. S S X 4 84 Z QR 12 12 RQ 2 6 Y
2. Identify the pairs of congruent angles and corresponding sides. B 10 6 A S 11 59° 5. 5 3 C R 5 T
Determine if the polygons are similar. If so, write the similarity ratio and a similarity statement. 4. Q 3. B 6 9 C F G 10 4 E A 6 D H P 36° T 10 R 5 S 62° 5 W
Whiteboards 5. Determine if the polygons are similar. If so, write the similarity ratio and a similarity statement. J 6. Q P 75 L 60 45 24 M N T 30 18 12 S P 16° 4 12 R 9 S 82° 3 9 W
Do on white boards! 7. Find the length of the model to the nearest tenth of a centimeter. 5 m 2 m Race car x 6 cm Model
Use similarity ratios to solve for the missing side J 1. P 4 10 x N L 8 2. S B M 6 C F E A D Q T 10 P 20° 4 G x 3 3. 3 10 R 5 80° S x 5 W H
You try… X 1. Identify the pairs of congruent angles and A corresponding sides. B C Y Z 2. Determine if the parallelograms are similar. If so write the similarity ratio and similarity statement. If not U 5 2 84 G explain why not. H 35 E F T V 60 W 3. Leonardo da Vinci’s famous portrait, the Mona Lisa, is 30 in long and 21 in wide. Janelle has a refrigerator magnet of the painting that is 3. 5 cm wide. What is the length of the magnet?
Assignment P 375 # 1 -16
