Ratios and Proportions Flashcard

Front

What is a ratio?

Back

A ratio is a comparison of two quantities that shows the relative size of one quantity to another, often expressed as 'a to b' or a:b.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal, often written as a/b = c/d.

Front

How do you find the cost per item using a ratio?

Back

To find the cost per item, divide the total cost by the number of items. For example, if a pizza costs $12 and has 8 slices, the cost per slice is $12 ÷ 8 = $1.50.

Front

If there are 5 ice cream cones for every 3 brownies, how do you find the number of cones sold if 24 brownies were sold?

Back

Set up a proportion: 5 cones/3 brownies = x cones/24 brownies. Cross-multiply and solve for x: x = (5 * 24) / 3 = 40 cones.

Front

What is a unit rate?

Back

A unit rate is a ratio that compares a quantity to one unit of another quantity, often expressed as 'x per 1 unit of y'. For example, 30 cm of snow in 6 hours is 5 cm of snow per hour.

Front

How do you simplify a ratio?

Back

To simplify a ratio, divide both terms of the ratio by their greatest common divisor (GCD). For example, the ratio 10:15 can be simplified to 2:3.

Front

What is the scale in a scale drawing?

Back

The scale in a scale drawing is the ratio of the drawing's dimensions to the actual dimensions. For example, a scale of 4 cm:9 ft means 4 cm in the drawing represents 9 ft in reality.

Front

How do you calculate the actual size from a scale drawing?

Back

To calculate the actual size from a scale drawing, use the scale ratio. If the drawing is 11 cm and the scale is 4 cm:9 ft, the actual size is (11 cm * 9 ft) / 4 cm = 24.75 ft.

Front

What does it mean if two ratios are equivalent?

Back

If two ratios are equivalent, it means they represent the same relationship between quantities, and they can be expressed as a proportion.

Front

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

Back

To find the number of items in a ratio, use the total quantity and the parts of the ratio. For example, if the ratio is 2:3 and the total is 25, then 2 parts + 3 parts = 5 parts. Each part is 25 ÷ 5 = 5, so there are 10 and 15 items respectively.