Proportions

Front

What is a proportion?

Back

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

Front

If a/b = c/d, what can be inferred?

Back

If a/b = c/d, then ad = bc (cross-multiplication).

Front

Solve for r: 8/4 = r/8

Back

r = 16.

Front

Solve for x: 4/6 = 10/(x-8)

Back

x = 23.

Front

Solve for r: 10/9 = (r+10)/(r-3)

Back

r = 120.

Front

Solve for b: (b+9)/(b+3) = 8/6

Back

b = 15.

Front

Solve for b: b/(b-2) = 6/10

Back

b = -3.

Front

What is cross-multiplication?

Back

Cross-multiplication is a method used to solve proportions by multiplying the numerator of one ratio by the denominator of the other ratio.

Front

What does it mean if two ratios are equivalent?

Back

It means that they represent the same relationship between quantities.

Front

How can you check if two fractions are in proportion?

Back

You can check by cross-multiplying and seeing if the products are equal.