The document contains examples of using formulas to solve problems. It provides formulas for distance, rate, and time (d=rt); perimeter (P=2l+2w); estimating temperature based on cricket chirps per minute (F=n/4+37); and finding the perimeter of a room. It works through applying these formulas to calculate average speed from a distance and time, estimate temperature, and find the perimeter of a room.

1. 3.4 formulas October 07, 2011
Objective ­ use formulas
Evaluate each expression for
x = 3 and y = 4
1. 2x + 2y Be
2. 2x + y llw
3. x + y
2
ork
HW pg. 145 #1­22 1

2. 3.4 formulas October 07, 2011
formula ­ an equation that shows a relationship between
quantities that are represented by variables.
d = rt
Suppose you travel 162 miles in 3 hours. Use the formula
d = rt to find your average speed.
HW pg. 145 #1­22 2

3. 3.4 formulas October 07, 2011
d = 273 mi, t = 9.75 h d = 540.75 in, r = 10.5 in/yr
HW pg. 145 #1­22 3

4. 3.4 formulas October 07, 2011
n
F = + 37
4
You can estimate the temperature outside using the chirps of a cricket.
Use the formula where n is the number of times a cricket chirps per minute,
and F is the temperature in degrees Fahrenheit.
Estimate the temperature when a cricket chirps 100 times in a minute.
HW pg. 145 #1­22 4

5. 3.4 formulas October 07, 2011
Perimeter ­
P = 2l + 2w
Find the perimeter of the room. 12.5 ft
18.5 ft
HW pg. 145 #1­22 5

6. 3.4 formulas October 07, 2011
HW
pg
145
# 1
­ 2
2
HW pg. 145 #1­22 6