Solving Proportions

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 two ratios and set the products equal to each other.

Front

If 4 pages take 18 minutes, how do you find the time for 30 pages?

Back

Set up a proportion: 4/18 = 30/x, then cross-multiply and solve for x.

Front

What is the formula for finding speed?

Back

Speed = Distance / Time.

Front

If a car travels 120 miles in 3 hours, what is its speed?

Back

Speed = 120 miles / 3 hours = 40 miles per hour.

Front

How do you calculate earnings per hour?

Back

Divide total earnings by total hours worked.

Front

If you earn $60 for 8 hours of work, how much do you earn per hour?

Back

$60 / 8 hours = $7.50 per hour.

Front

What is the formula for calculating percentage?

Back

Percentage = (Part / Whole) x 100.

Front

If Shirley spelled 12 out of 15 words correctly, what is her percentage score?

Back

(12 / 15) x 100 = 80%.

Front

What is the relationship between height and shadow length in similar triangles?

Back

The ratio of the height of an object to the length of its shadow is constant.