solve proportions using mental math

Solve the proportion:

• c = 4

• c = 8

• c = 14

• c = 10

Solve for x 

• x = 16
• x = 28
• x = 1/26
• x = 26

What is a proportion?

• When two ratios can be simplified
• When two ratios are equivalent and show the same value
• When two ratios have the exact same numbers
• When two ratios can be multiplied by 2

A car travels 50 km in 40 minutes.

How many km does the car travel in 20 minutes?

• 25 km

• 60 km

• 1.25 km

• 70 km

Solve the proportion.

• k=5
• k=3.3333333
• k=60
• k=90

• 1
• 3

• 4
• 12

Solve the proportion:

• 15
• 5
• 10
• 12

A recipe called for the ratio of sugar to flour to be 10:3. If you used 50 ounces of sugar, how many ounces of flour would you use?

• 21

• 15

• 13

• 120

Solve for x 

• x = 1/10
• x = 10
• x = 4
• x = 5