SCALE FACTOR
Objective: Show/Hide
The student will be able solve problems related to scale drawings
Standards: Show/Hide
7.5 Proportionality. The student applies mathematical process standards to use geometry to describe or solve problems involving proportional relationships. The student is expected to:
(C) solve mathematical and real-world problems involving similar shape and scale drawings 
Success Criteria: Show/Hide
The student will be able to identify the corresponding parts of similar figures, determine the scale factor used, and solve problems involving scale drawings.
Definition: Show/Hide
A scale drawing of an object, has de same shape as the real object, but has different size (is an enlarged or diminished version of the original).
Mini Lesson: Show/Hide
Mom is pregnant and soon we will have a little sister. My dad says he wants to build an extra room in our house for her. Dad tells me that the minimum size of the new bedroom should be 90 square feet.
He asked me to make a scale map of our house (in which an inch in the plane equals one foot in the house). I plan to make the scale map of our house, drawing all the length dimensions in proportion (one inch in the plane equals one foot in the house). On the drawing, I draw the new bedroom with dimensions of 10 by 12 inches. Do you think that size is adequate?
Scale Factors in Daily Life: Show/Hide
Engineers use scale factors in maps, blueprints, diagrams and scale models.
When building a house or a building we make the drawing on a scale.
In the kitchen we scale a recipe to the amount of servings we need (enlarging or reducing the amount of ingredients)
Vocabulary: Show/Hide
Scale ios the relationship between a measurement on a model and the real measurement of the original thing.
Scale factor is the ratio of the measure in a model to the measure of the original thing.
A scale drawing is a two-dimensional representation of an object
Resources: (from MsGarciaMath) Show/Hide
Scale Drawing Video
SF10 Similar Rectangles 1 Worksheet
SF06 Scale Perimeter Worksheet
AR04 Scale Area Worksheet
SF01 Scale Drawing Worksheet
SF02 Scale_Factor Worksheet
Example Problems: Show/Hide
A house has a rectangular distribution and its exterior measures 22 by 36 feet. An engineer is making a scale drawing of the house in which every 2 inches in the blueprint correspond to 3 feet in real measuerement. What are the dimensions of the scale drawing?
Solution
If the following triangle is enlarged using a scale factor of 2.8, what will be the perimeter and area of the new triangle?
Solution
A map has a scale of 1 cm: 20 Km. If two cities are 7.2 cm apart in the map, how far are actually apart?
Solution
Find the actual length and width of the figure represented by the following scale drawing. The scale factor is 1 cm: 2.5 m
Solution