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Materials DE Marker 15 Small White Boards Reminders Use similar triangles to find the length of side x: 6 7.5 10 x 150 Get out your agenda if you see your name below. You need to come to my room tomorrow. Period 4 Period 5 Period 6 Stretching and Shrinking: Scale and Scale Factor How do I determine scale and scale factor between models and reality? Questions: What does scale mean? Notes: Scale – the ratio of a length on a drawing or model to the length of an actual object Note: a Scale can have different units Example: Questions: What does scale factor mean? Notes: Scale Factor – gives how many TIMES larger or smaller an object is Note: a Scale Factor must have the same units and can be written using a colon (ex. 1:23,000) Example: 1:16,000,000 1:1,300,000 Questions: How do I write scale? Notes: Example: A map shows 2 inches = 6 feet Write this as a ratio: 2 𝑖𝑛𝑐ℎ𝑒𝑠 6 𝑓𝑒𝑒𝑡 1 𝑖𝑛𝑐ℎ = 3 𝑓𝑒𝑒𝑡 Simplify so that the numerator has a length of one. 1 𝑐𝑚 = 2 𝑚𝑒𝑡𝑒𝑟𝑠 3 (3)1 𝑐𝑚 = (3)2 𝑚𝑒𝑡𝑒𝑟𝑠 3 1 𝑐𝑚 = 6 𝑚𝑒𝑡𝑒𝑟𝑠 Questions: How do I determine scale factor? Notes: Make sure both amounts are using the SAME UNITS. 1 inch on a map = 10 feet in reality Since there at 12 inches in a foot 1 inch = 10(12) inches 1 inch = 120 inches 1:120 The scale factor from the map to reality is 120. THIS MEANS THAT IF WE MULTIPLY A MEASURMENT ON THE MAP BY 120, WE WILL GET THE LENGTH IN THE REAL WORLD. Class Activity 1. Work on WS 5-8 Practice A with your table partner 2. We will work the problems together 3. Be prepared to share with the class Class Activity Class Activity Class Activity Class Activity Class Activity Class Activity Class Activity Class Activity Class Activity Homework WS 5-8 Practice A and B AND Cornell Notes Summary