Ratios & proportions

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division, showing how many times one value contains or is contained within the other.

Front

How do you write a ratio?

Back

Ratios can be written in three ways: as a fraction (e.g., 5/4), with a colon (e.g., 5:4), or with the word 'to' (e.g., 5 to 4).

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the terms and then solve for the unknown variable.

Front

If the ratio of boys to girls is 5:4 and there are 32 girls, how many boys are there?

Back

40 boys.

Front

What is the formula for finding a missing value in a proportion?

Back

Front

If a telephone booth is 8 ft tall and casts a shadow of 4 ft, what is the height of an object that casts a 2 ft shadow?

Back

4 ft.

Front

How do you find the total number of items in a ratio?

Back

Add the parts of the ratio together. For example, in a ratio of 5:4, the total is 5 + 4 = 9.

Front

What is the ratio of pears to all fruit if there are 4 apples, 2 bananas, and 5 pears?

Back

5:11.

Front

If hamburger meat costs $6 for every 3 pounds, how much does 10 pounds cost?

Back

$20.