algebra readiness
DESCRIPTION
Algebra Readiness. Chapter 1 Section 3. Lesson 1.3 Use Formulas. Vocabulary and Concepts: A variable is a letter used to represent one or more numbers. A formula gives a relationship between two or more variables. Some common formulas are as follows:. - PowerPoint PPT PresentationTRANSCRIPT
Algebra Readiness
Chapter 1 Section 3
Lesson 1.3 Use Formulas
Vocabulary and Concepts:A variable is a letter used to represent
one or more numbers. A formula gives a relationship between
two or more variables. Some common formulas are as follows:
Perimeter and Area of a Rectangle
The perimeter p of a rectangle with length l and width w is :
P=2l + 2w
The area A of a rectangle with length l and width w is:
A = lw
Perimeter and Area of a Square
The perimeter p of a square with side length s is:
P =4s
The area A of a square with side length s is:
A = s²
Distance, Rate, and Time
Distance traveled d is equal to the speed (rate of travel) r times the travel time t.
d=rt
Total Cost
The total cost T of n items is the cost c of one item (the unit cost) times the number of items.
T=cn
Example 1
International soccer is played on a rectangular field that has a length of 100meters and a width of 64 meters. What are the perimeter and the area of the soccer field?
Finding Perimeter and Area
SOLUTION
2w2lP += Write perimeter formula.
Substitute 100 for l and 64 for w.22 += ( )100 ( )64
Multiply.128200 +=
Add.328=
You Try:
A picture frame holds a picture that has a length of 6 inches and a width of 4 inches. What are the perimeter and the area of the picture?
Answer: What is the length?
6 in. What is the width?
4 in. What is the formula for perimeter for this shape?
P= 2l + 2w P = 2(6) + 2(4)
= 12 + 8 = 20 in. What is the formula for area for this shape? A=lw
A=6(4)= 24 in.²
Example 2: Finding distance traveled.
A sea turtle travels at an average rate of about 20 kilometers per day. How far can a sea turtle travel in 4 days?
d = rt
= 20 · 4
= 80 km
Write the formula for distance traveled.Substitute 20 for r and 4 for t.
Multiply.
A sea turtle can travel 80 kilometers in 4 days.
Example 3: Finding total cost.
A school is purchasing 35 microscopes that cost $119 each for the science department. What is the total cost?
T = cn
= 119 · 35
= 4165
Write the formula for total cost.Substitute 119 for c and 35 for n.Multiply.
The total cost for 35 microscopes that cost $119 each is $4165.
You Try:
Kayla bought 26 jars of poster paint. She paid $3 for each jar. What was the total cost?
Answer:
What is the formula for finding total cost?T = cn
What is the cost of one item?$3
What is the number of items?26
T = 3 · 26 = $78