Math Vocabulary: Scaling Figures

Math Vocabulary: Scaling Figures

Understanding the words to understand the problems

Key words

• Ratio

• Scale Drawing

• Scale

• Scale Factor

• unit rate

• units

Ratio

A ratio compares values.

A ratio says how much of one thing there is compared to another thing. Ratios can be shown in different ways:

Use ":" to separate the values: 3 : 2   

Or we can use the word "to"  3 to 2   

Or write it like a fraction: 3/2

Multiple Choice

Which one is NOT a ratio

• 15 and 3

• 15 : 3

• 15 to 3

• 15/3

Open Ended

How would you explain to someone, what a ratio is?

Scale drawing

A scale drawing is the same shape but a different size as the original object

A drawing that shows a real object with accurate sizes reduced or enlarged by a certain amount (called the scale factor).

Multiple Choice

A scale drawing is

• a drawing of something that is the same shape but a different size

• a drawing of something that is the same size but a different shape

Open Ended

How would you explain to someone, what a scale drawing is?

Scale

a ratio between two measurements, usually between a measurement on a scaled drawing and the actual measurement.

Often seen on maps and floorplans. Scale will always be a ratio between two numbers and include units.

(note: if the units are the same on both sides, they are sometimes left off)

Multiple Select

What are the parts of a scale?

(Pick two)

• ratio, comparing measurements of two figures

• units, telling us what type of measurement we are using

• equal sign, telling us what one thing equals

Open Ended

How would you explain to someone, what a scale is?

Scale Factor

The scale factor is the number you multiply each measurement to scale up (enlarge) or scale down (reduce) a shape.

If you are scaling up a shape the scale factor must be more than 1

If you are scaling down a shape the scale factor must be less than 1 (usually a fraction)

Multiple Select

A scale factor can be

(pick two)

• a number larger than 1, if scaling up.

• a number smaller than 1 (a fraction), if scaling down

• a scale, that describes a relationship between two numbers using units

• an invisible 6 ft rabbit, called Harvey

Open Ended

How would you explain to someone, what a scale factor is?

Unit Rate

A Unit Rate is a special kind of ratio that must always have a 1 in it. It tells you have how much of something per 1 unit of something else.

Sometimes a scale is a unit rate, but only if the scale as a 1 on one side of it.

If 100 cars pass by in 2 hours. The unit rate is 50 cars per hour. 50 : 1

Multiple Choice

How is a unit rate different than a scale?

• a scale doesn't need to have a one in it.

• a unit rate can have any numbers on either side of the ratio

• unit rate can not have a 1 in it.

Open Ended

How would you explain to someone, what a unit rate is?

Units

A unit is any measurement that there is 1 of.

So 1 meter is a unit.

And 1 second is also a unit.

Units can measure length, width, height, depth, weight, and many other things

Some units are:

inches, feet, yards, miles, centimeters, meters, Kilometers, pounds, gallons, and even lightyears

Multiple Choice

True or False?

Units tells us what kind of measurement is in the problem. Sometimes they can help us see if we are dealing with scale measurements or actual measurements.

• true

• false

Open Ended

How would you explain to someone, what units are?