Similar Figures and Scale Drawings

1. Similar Figures and Scale Drawings

2. Similar Figures • Have the same shape but not the same size • Have corresponding angles and sides

3. Similar Figures cont… • Properties • Corresponding angles have equal measures • Lengths of corresponding sides are proportional

4. Similar Figures cont… • Ex: 16 24 A B E F x 18 D C H G

5. Similar Figures cont… • X = 16 18 24 24x = 18 * 16 24x = 288 24 24 x = 12

6. Indirect Measurements • Method of determining the length of something without measuring it directly

7. Indirect Measurements cont… • EX: 5ft woman casts a 4ft shadow and a tree casts a 10ft shadow. How tall is the tree? shadow proportion/length proportion

8. Indirect Measurements cont… • woman’s shadow 4ft = 5ft woman’s height tree’s shadow 10ft t tree’s height 4t = 5 * 10 4t = 50 4 4 t = 12.5 ft

9. Scale Drawings • Enlarged or reduced drawing that is similar to the actual object or place—used with maps and models • Scale—ratio of distance in the drawing to corresponding to actual distance • You can use proportions to solve

10. Scale Drawings cont… • EX: A scale on a map is 1in : 40miles the distance between 2 cities on a map is 1 ½ inches. How many miles? map distance actual distance

11. Scale Drawings cont… • EX cont… 1 = 1.5 40 d 1d = 40 * 1.5 d = 60

12. Scale Drawings cont… • Dilation – scale drawing that increases the size of a figure/object