1. Multiplication and Division of Fractions
Section 4.3
Multiplication and Division of Fractions

2. Topics Covered Multiplication of fractions Area of a Triangle
Reciprocals
Division of Fractions
Applications

3. Multiplication of Fractions
To multiply fractions, write the product of the numerators
over the product of the denominators.
Make sure that your answer is fully reduced
Examples:

4. Multiply Fractions w/Variables
Examples:
3𝑤 11 ∙ 5 6𝑤 𝑥 3 6𝑦 ∙ 𝑦 2 𝑥
Try:
7𝑧 12 ∙ 4 𝑧 𝑤 3 𝑧 4 ∙ 𝑧 2 28𝑤

5. Multiplying Fractions on the TI-34
To multiply
Enter the first fraction 2/3
Press the right arrow to exit the 1st fraction
Press the multiplication button
Enter the 2nd fraction 6/7
Press [enter]
Use the [simp] key to simplify your answer.
Note: you may have to use the [simp] key more than once to
fully reduce your answer.

6. Area of a Triangle
The area of a triangle is calculated with the following formula:
Where b is the base of the triangle and h is the height of the triangle.

7. Find the area of a triangle whose base is 5/8 ft and whose height is 4/15ft
20 / 240 ft squared
5 / 60 ft squared
1/12 ft squared
1/ 6 ft squared

8. The Reciprocal of a Fraction
To find the reciprocal of a fraction interchange the numerator
and the denominator.
Other way of thinking about it is that you flip the fraction
upside down.
Examples:

9. Division of Fractions “Keep it, Change it, Flip it”
Keep the 1st fraction
Change division to multiplication
Flip the 2nd fraction
Examples:

10. Dividing Fractions on the TI-34
To multiply
Enter the first fraction 7/8
Press the right arrow to exit the 1st fraction
Press the division button
Enter the 2nd fraction 14/24
Press [enter]
Use the [simp] key to simplify your answer.
Note: you may have to use the [simp] key more than once to
fully reduce your answer.

11. Dividing Fractions with Variables
Examples:
5 𝑦 ÷ 𝑥 2 𝑦 2
8 𝑦 3 7 ÷ 4𝑦 5

12. Application #1
A developer sells lots of land in increments of ¾ acre. If the developer has 60 acres, how many lots can be sold?

13. Application #2
If 1 centimeter (cm) is 1/100 meter (m), how many centimeters are there in a 5/4 m piece of rope?

14. Application #3
Althea wants to buy a Toyota Camry for a total cost of $18,000. The dealer requires 1/12 of the money as a down payment. Athea’s parents have agreed to pay one-half of the down payment for her.
a. How much money will Athea’s parents pay toward the down payment?
b. How much will Althea pay toward the down payment?
c. How much will Althea have to finance?