1. Proportions and Scale Drawings Textbook Pages 417-422

2. Objective I can solve scale drawing problems using proportions.

3. Vocabulary Scale Drawing: is the same shape but not the same size. A map is a scale drawing. The units are very important. Scale: tells us how the drawings dimensions and the actual dimensions are related. (Ratio) The standard way to write the scale is scale model to actual object or scale:actual

4. Interpreting Scale Drawing 3 inches The scale is 1 in. : 5ft Find the actual length of the canoe. 1in 3 in. 5ft ?ft What did you do to 1 to get to 3. Multiplied by 3. So multiply 5 by 3 to get 15 ft.

5. Scale 1 in : 8ft If the scale model is 4 inches; What is the actual? 32 feet If the actual is size is 40 feet, what is the scale model? 5 inches

6. Try some! The scale of a drawing 2 in.: 6m Length of the drawing = 8in. Length of object = __________ Length of object = 36 m Length of drawing = __________

7. Word Problems You are building a model boat with a scale of 1 in.:2ft. The actual boat is 18 feet long. How long should you make your model? 9 inches

8. Using it to find area and perimeter. A scale drawing of this classroom is 2cm by 3 cm. The scale is 1cm:2m. What is the area of the classroom? Covert both measurements to make the actual length and width. 1cm 2cm1cm 3cm 2 m w 2m L Width is 4 mLength is 6 m Area is 4 x 6 = 24m squared

9. Draw a diagram Using the scale 1in.:10ft, make a scale drawing of a 30ft by 40 foot dance floor. You should have a 3in by 4 in drawing Use your drawing to find the actual distance from opposite corners. If you measured on your scale drawing you would find it to be 5 inches. Using the scale it would convert to 50 ft.

10. Practice Workbook Pages 107-108 1-12