Solving Proportions

Solving Proportions

Lesson 5.4

Using Mental Math

• You can use mental math to solve a proportion.

•  $\frac{3}{2}=\frac{x}{8}$  

•  $\frac{5}{7}=\frac{x}{21}$  

Multiple Choice

A school has a total of 950 students. The ratio of female students to all students is 48/95. Write and solve a proportion to find the number of female students.

• 95

• 48

• 480

• 950

Using Cross Products

• You can use cross products to solve a proportion.

• Set up an equation using cross multipliation.

• Solve the equation.

•  $\frac{x}{8}=\frac{7}{10}$  

•  $\frac{x+1}{9}=\frac{20}{6}$