Presentation on theme: "5.7 Scale Drawings and Models"— Presentation transcript:
15.7 Scale Drawings and Models Standard: MG 1.3Objective: Students use scales, ratios, and proportions to solve scale drawing and model problems.
2Key ConceptsScale 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.
3Key ConceptMaps, globes, Google maps, blueprints, and model cars are all examples of scale drawings and/or models.It makes it easier tounderstand large objects.
4Example 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.
5Practice 1 The scale on a map reads 1 cm : 200 m. Find the actual distance if the distance measured on themap is 7 cm.5
6Find the actual distance from LA to Houston. miScale1 in : 300 mi6
7Example 2: Find scaleJust like in example 1, use a proportion to find the missing value.
8Practice 2A 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?
9Example 3: Find dimensions First change the scale to equal units (inches)Then write and solve the proportion
10The 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 mapdimensions x and y.yScale1 in : 8 ftxLengthWidth10
11Review What is a scale model or drawing? What is a scale? How do you solve scale problems?Give an example of when a scale is used.