1. Evaluating More Formulas
Lesson 9
Introductory Algebra
Evaluating More Formulas

2. Warm-Up Find the perimeter of a rectangle using the formula
P = 2l + 2w when l = 1.5 and w = 3.2.
Find the value of a2 + k when a = 5 and k = 7.
Find the value of as a decimal.

3. Evaluating More Formulas
Target:
Use formulas in a variety of situations.

5. Example 1
A family traveled from Medford, Oregon to Salem, Oregon in a small sedan. They traveled for 4 hours at a speed of 58 miles per hour. How many miles did they drive from Medford to Salem? Use the formula d = rt where d is the distance, r is the rate and t is the time.

6. Example 2 Petrik jogs at a speed of 7 miles per hour. He jogs for 30
minutes. How far has he traveled?
30 minutes = hour

7. Example 3 A professional baseball player had 555 ‘at bats’ in one
season. He had a total of 189 hits during that season.
What was his batting average?
Use the formula where B is batting average, h is
hits and a is ‘at bats’.

8. Exit Problems
Find the amount of interest when p = $3000, r = 6% and t = 4 years.
Find Greg’s batting average if he has had 22 hits during 75 ‘at bats’.
Owen drove for 5 hours at a rate of 58 miles per hour. How far did he drive?

9. Communication Prompt
Write three math “story problems” that use the formulas you learned today. Solve each of your problems.