Unit 3 Rates and Ratios Review

Front

What is a ratio?

Back

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

Front

How do you convert a percentage to a decimal?

Back

To convert a percentage to a decimal, divide the percentage by 100. For example, 40% becomes 0.40.

Front

What is the formula to find a percentage of a number?

Back

To find a percentage of a number, multiply the number by the percentage (as a decimal). For example, to find 40% of 230, calculate 230 x 0.40 = 92.

Front

How many milligrams are in a gram?

Back

There are 1,000 milligrams in a gram.

Front

If the boy to girl ratio is 1:3, how many girls are there if there are 40 students?

Back

If the ratio is 1:3, then for every 1 boy, there are 3 girls. In 40 students, there are 10 boys and 30 girls.

Front

What is a scale on a map?

Back

A scale on a map shows the relationship between a distance on the map and the actual distance it represents.

Front

If the scale on a map is 5 cm : 12 km, how do you find the distance on the map for 144 km?

Back

To find the distance on the map, set up a proportion: 5 cm / 12 km = x cm / 144 km. Solving gives x = 60 cm.

Front

How do you calculate the rate of change?

Back

The rate of change is calculated by dividing the change in quantity by the change in time. For example, if Fred got 48 pieces of candy in 4 hours, the rate is 48 / 4 = 12 pieces per hour.

Front

What is the relationship between ratios and fractions?

Back

Ratios can be expressed as fractions. For example, a ratio of 1:2 can be written as 1/2.

Front

How do you simplify a ratio?

Back

To simplify a ratio, divide both terms by their greatest common divisor (GCD). For example, the ratio 4:8 simplifies to 1:2.