Presentation on theme: "5.7 Scale Drawings and Models Standard: MG 1.3 Objective: Students use scales, ratios, and proportions to solve scale drawing and model problems."— Presentation transcript:
5.7 Scale Drawings and Models Standard: MG 1.3 Objective: Students use scales, ratios, and proportions to solve scale drawing and model problems.
Key Concepts Scale drawing: a 2D drawing of an object reduced to a proportion of the original object. Scale model: a 3D model of an object reduced to a proportion of the original object. Scale: the ratio of the dimensions of the large object to the reduced model.
Key Concept Maps, globes, Google maps, blueprints, and model cars are all examples of scale drawings and/or models. It makes it easier to understand large objects.
Example 1: Find measurement Since the distance must be proportional to the scale, write and solve a proportion to find the missing value. Make sure units match when setting up the proportion.
The scale on a map reads 1 cm : 200 m. Find the actual distance if the distance measured on the map is 7 cm. Practice 1
1 in : 300 mi 0 1 in 0 300 mi Find the actual distance from LA to Houston. Scale
Example 2: Find scale Just like in example 1, use a proportion to find the missing value.
Practice 2 A blueprint shows a house that is 15 cm long and the actual house is 75 m. The scale is 1 cm : ? m. What is the scale?
Example 3: Find dimensions 1)First change the scale to equal units (inches) 2)Then write and solve the proportion
The scale of the house blueprint below is to be 1 in = 8 ft. If the actual dimensions are 80 ft. by 30 ft., find the map dimensions x and y. x y Scale 1 in : 8 ft LengthWidth
Review 1)What is a scale model or drawing? 2)What is a scale? 3)How do you solve scale problems? 4)Give an example of when a scale is used.