1. Do Now 1/17/12 Take out HW from Friday. Take out HW from Friday.  Practice worksheets 4.5 B & C Copy HW in your planner. Copy HW in your planner.   Text p. 174, #1-12 all, 15, 16, 19, & 20   Measurements of your bedroom (length & width) and at least 4 objects (bed, dresser, desk, etc…)   Quiz sections 4.4 – 4.6 Friday   Chapter 4 Test Tuesday 1/24 Be ready to copy POTW #7 Be ready to copy POTW #7

2. Homework Practice worksheet 4.5 B & C 1) 60 cm 2) 44° 3) 21° 4) 12 in 5) 2.8 ft 6) 16.5 ft 1) 21.6 yd 2) 56° 3) 26° 4) 22.1 m 5) 9.5 meters 6) 28 feet 7) 225 inches 8) 112 feet

3. Objective SWBAT understand ratios and proportions in scale drawings and use ratios and proportions with scale

4. Section 4.6 “Scale Drawings and Scale Models” SCALE DRAWING- A proportional two-dimensional drawing of an object. Its dimensions are related to the dimensions of the actual object by a ratio called the SCALE FACTOR.

5. Identify the scale factor. 13.5108Width (in.)‏ 18144Length (in.)‏ BlueprintRoom blueprint length room length = 1818 18 144 = A scale factor is always the ratio of the model’s dimensions to the actual object’s dimensions. Caution! 318Wing span (in.)‏ 212Length (in.)‏ BlueprintModel Aircraft blueprint length aircraft length = 2 12 = 1616

6. SCALE - the SCALE of a drawing, map, or model relates the dimensions of the drawing, map, or model to the actual dimensions. Write and solve a proportion to find the distance d between Cleveland and Cincinnati if the distance on the map is about 4.2 centimeters. Write and solve a proportion to find the distance d between Cleveland and Cincinnati if the distance on the map is about 4.2 centimeters. = 4.2 d 1centimeters 85 kilometers Cross products property d = 357 Simplify. 1 d = 85 4.2

7. SCALE MODEL- A proportional three-dimensional model of an object.

8. A dinosaur model kits sold at a hobby store has a scale of 1 ft : 25 ft. A completed model of the dinosaur is 1.6 feet long. Estimate the actual length of the dinosaur. A dinosaur model kits sold at a hobby store has a scale of 1 ft : 25 ft. A completed model of the dinosaur is 1.6 feet long. Estimate the actual length of the dinosaur. Write and solve a proportion to find the length g of the dinosaur. =1.6 g 125 Cross products property g = 40 Simplify. 1 ∙ g = 25 ∙ 1.6 SOLUTION The actual length of the dinosaur is about 40 feet.

9. A model of a space shuttle has a scale of 1 : 52. The space shuttle has a wingspan of 78 feet. Find the model’s wingspan. A model of a space shuttle has a scale of 1 : 52. The space shuttle has a wingspan of 78 feet. Find the model’s wingspan. Write and solve a proportion to find the wingspan w of the space shuttle. = w 78 78 152 Cross products property 1.5 = w Simplify. 1 ∙ 78 = 52 ∙ w SOLUTION The wingspan of the model is 1.5 feet.

10. A scale drawing of a basketball court has a scale of 1 inch : 9 feet. The basketball court is 94 ft by 50 ft. Find the dimensions of the court in the scale drawing. L = 10 4/9in 1 ∙ 94 = 9 · L W = 5 5/9in 1 ∙ 50 = 9 ∙ W

11. A scale drawing of a basketball court has a scale of 1 inch : 9 feet. The free throw line is 15 feet from the backboard. How far is it in the scale drawing? b = 1 2/3in 1 ∙ 15 = 9 · b

12. Homework Text p. 174, #1-12 all, 15, 16, 19, & 20 NJASK7 Prep