Learning Log #8 Scale Factor A B A 20m 64m 5m 256m A

Learning Log #8 - Scale Factor A B A 20m 64m 5m 256m A This side corresponds to this side. And you need to ask yourself, what multiplied by 5 makes 20? Or you could simply do 20 ÷ 5 = 4. 4 is our scale factor from B to A because 5 * 4 = 20m. The reverse, A to B, 20 * ¼ = 5. We get ¼ by using the reciprocal of 4. Remember, Scale Factor is always expressed as multiplication not division. Always start by asking yourself “which side corresponds to which side?” Reminder You must always say Scale Factor with direction. Example: “The scale factor of B to A is…”

Learning Log #8 Scale Factor “How do they compare?” A B A 24m 3m 4m 18m A SF =* 1/6 SF=*6 Scale Factor from A to B is 1/6 because 30m * 1/6 = 5m 24m *1/6 is 4m B to A is 6 because 5m * 6 = 30m 4m * 6 = 24m SF & Area Area of B is 6m ² Scale Factor B to A is 6 & 6 ² = 36 Area * SF ² = Area of A 36*6m² = 216 m² B to A the area is 36 times larger. SF & Perimeter Perimeter of B is 12m Scale Factor B to A is 6 P * SF = Perimeter of A 12m * 6 = 72m 72m is the perimeter of A B to A the Perimeter is 6 times larger. 30m 5m SF & Side Lengths The side-lengths from B to A are 6 times larger.

Scale Factor: Area & Perimeter  Perimeter 1 st P * SF = 2 nd P Variables Defined P = perimeter 1 st P = 1 st perimeter 2 nd P = 2 nd perimeter SF = Scale Factor  Area 1 st A * SF ² = 2 nd A Variables Defined A = Area 1 st A = 1 st Area 2 nd A = 2 nd Area SF = Scale Factor Angles And remember, if two images are similar the angles remain the same!