Day 149 -Setting Up Proportions

Front

What is a proportion?

Back

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

Front

How do you set up a proportion?

Back

To set up a proportion, you can use the formula a/b = c/d, where a and b are the first ratio, and c and d are the second ratio.

Front

If a car travels 420 miles in 8 hours, what is its speed in miles per hour?

Back

Speed = Distance/Time = 420 miles / 8 hours = 52.5 miles per hour.

Front

How do you find the missing value in a proportion?

Back

Cross-multiply the known values and solve for the unknown value.

Front

If Pat needs 14 sticks of pepperoni for 28 pizzas, how many sticks are needed for 1 pizza?

Back

14 sticks / 28 pizzas = 0.5 sticks per pizza.

Front

If 36 pizzas require how many sticks of pepperoni?

Back

0.5 sticks/pizza * 36 pizzas = 18 sticks of pepperoni.

Front

What is the ratio of boys to total students in Ms. King's class?

Back

The ratio is 16 boys to 25 total students, or 16/25.

Front

If the class size increases to 40 students, how many boys would there be?

Back

(16 boys / 25 students) = (x boys / 40 students) => x = (16/25) * 40 = 25.6, round to 26 boys.

Front

How do you calculate the duration a larger bottle of shampoo will last?

Back

Use the ratio of the sizes of the bottles and the duration the smaller bottle lasts.

Front

If 12 ounces last 16 weeks, how long will 18 ounces last?

Back

(12 ounces / 16 weeks) = (18 ounces / x weeks) => x = (18 * 16) / 12 = 24 weeks.