1. Using Formulas

2. A FORMULA is an open sentence EQUATION that often has more than one variable.

3. One formula used in math and science is d = rt where d is the distance, r is the speed, and t is the time spent traveling.

4. Suppose you’re traveling to L. A. and you’ve been driving for 5
Suppose you’re traveling to L.A. and you’ve been driving for 5.5 hours at an average speed of 73mph. How far have you driven?

5. d = rt
So distance = 73 • 5.5
d = 401.5m

6. Use the formula d = rt. Let’s say you’ve been driving for 6 hours at a rate of 67mph. How far did you go?

7. The formula is d = rt
Distance = time • rate
d = 6 • 67
= 402miles

8. You found the area of rectangles for your warm-up today
You found the area of rectangles for your warm-up today. Let’s try to find their perimeters.

9. What is a perimeter? Think of the RIM around something
Distance AROUND a figure
For a rectangle, you can ADD the lengths of all four sides or…
Use the formula P = 2l + 2w where l is the length and w is the width.

10. Find the perimeter of Mr. Lau’s bathroom.
6ft
P = 2l + 2w
= 2(9) + 2(6)
9ft =
= 30ft

11. Using the formula P = 2l + 2w, find the perimeter of Mr
Using the formula P = 2l + 2w, find the perimeter of Mr. Lau’s backyard so that he can build a fence around it.

12. 30ft
P = 2l + 2w
= 2(30) + 2(52) =
52ft
= 164ft

13. Mr. Lau then wanted to fill the area with cement
Mr. Lau then wanted to fill the area with cement. Can you find the area of his backyard?

14. 30ft
A = lw
= 30(52)
= 1,560ft2
52ft

15. Now for your homework…