Math Vocabulary: Scaling Figures

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

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).

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)

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)

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

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