Perimeter, Circumference, and AreaBIG IDEA: MEASUREMENTESSENTIAL UNDERSTANDINGS:• Perimeter, circumference, and area are different

ways of measuring the size of geometric figures.• The area of a region is the sum of the areas of

its nonoverlapping parts.MATHEMATICAL PRACTICE:Look for and make use of structure

Getting Ready• You and your friend have two choices for a wall

decoration. You say the decoration on the top will use more wall space. Your friend says the two decorations will use the same amount of wall space. Who is correct? Explain.

The figures studied in this lesson have two dimensions

• Perimeter is the __________ of the lengths of its ____________ of the figure

• Circumference is the ____________ around a circle

• Area is the number of ____________ units enclosed by the figure

• Area Addition Postulate: The area of a region is the ________ of the areas of its _________________________ parts

Formulas• SQUARE

• TRIANGLE

• RECTANGLE

• CIRCLE

2

4

side length

P s

A s

s

2 2 , or 2

base; height

P b h b h

A bh

b h

1

2, , side lengths

base

height

P a b c

A bh

a b c

b

h

2

2 or

radius

diameter

C r d

A r

r

d

Examples• 1. To place a fence on the outside of a rectangular

garden with base 12 feet and height of 5 feet, how much material will you need?

• 2. A window has the shape of a rectangle with a half-circle on the top. The rectangle has a base of 3 feet and a height of 7 feet. Find the perimeter and area of the window.

Examples• 3. A circular compact disc fits exactly in a square box

with sides 12 centimeters long. Find the diameter, radius, circumference and area of the CD and the perimeter and area of the box.

Examples• 4. You are designing a rectangular flag for your city’s

museum. The flag will be 15 feet wide and 2 yards high. How many square yards of material do you need?

• 5. A painter is painting one side of a wooden fence along a highway. The fence is 926 feet long and 12 feet tall. The directions on each 5 gallon paint can say that each can will cover 2000 square feet. How many cans of pain will be needed to paint the fence?

Examples• 6. You are making a triangular window. The height of

the window is 18 inches and the area should be 297 square inches. What should the base of the window be?

• 7. What is the area of the figure below?

1.7 p. 556 – 22 evens, 13, 19, 21; 25, 26, 29, 30 – 48 evens, 4126 questions