Real-World Applications of Ratios and Percentages

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 calculate a percentage of a number?

Back

To calculate a percentage of a number, multiply the number by the percentage (in decimal form). For example, 20% of 192 is calculated as 192 * 0.20 = 38.4.

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 5 feet = 2 inches means that every 2 inches on the drawing represents 5 feet in reality.

Front

How do you find the actual height of an object from a scale drawing?

Back

To find the actual height, use the scale to convert the drawing measurement to the real measurement. For example, if a drawing is 10.5 inches tall and the scale is 5 feet = 2 inches, the actual height is (10.5 in * 5 ft) / 2 in = 26.25 ft.

Front

If 3 cans of green beans cost $2.50, how much does one can cost?

Back

To find the cost of one can, divide the total cost by the number of cans: $2.50 / 3 = $0.83 (approximately).

Front

How many cans of green beans can you buy for $10.00 if one can costs $0.83?

Back

To find the number of cans, divide the total amount by the cost of one can: $10.00 / $0.83 = 12 cans (approximately).

Front

What is the unit rate?

Back

The unit rate is a comparison of two different quantities when they are combined together. It is often expressed as a quantity per one unit of another quantity.

Front

If 2 hamburgers cost $9, what is the cost of one hamburger?

Back

To find the cost of one hamburger, divide the total cost by the number of hamburgers: $9 / 2 = $4.50.

Front

How do you calculate the cost of multiple items if you know the cost of one?

Back

Multiply the cost of one item by the number of items. For example, if one hamburger costs $4.50, then 10 hamburgers cost $4.50 * 10 = $45.00.

Front

If Ben purchased 4 oranges for $5, how much does one orange cost?

Back

To find the cost of one orange, divide the total cost by the number of oranges: $5 / 4 = $1.25.