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May 2012

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(easy hangman)
(difficult)

The ideas in this geometry lesson are taken from Math Mammoth Geometry 1 book.

Area Versus Perimeter

Some concepts and ideas of this lesson are also explained in this video:

Sometimes it's easy to confuse perimeter
and area. Just remember that

AREA has to do with covering. Your answer will be in "square" units.
PERIMETER has to do with “going all the way around”. Your answer will be in some unit of length.

Area: 4 cm × 8 cm = 32 cm².
Perimeter: 4 cm + 8 cm + 4 cm + 8 cm = 24 cm

1. Which one of perimeter, area, or volume fits each situation, if you need to find out...

a. how much fence is needed to go around a yard?

b. how much water fits into a bottle?

c. how big a carpet will cover the floor?

2. Find the area and perimeter of the rectangles. You can draw little tick marks to help.

a. 4 in. wide, 2 in. tall

Perimeter =
_____________

Area =
_________________

b. All sides are 4 cm.

Perimeter =
_____________

Area =
_________________

[available in the book]

3. The sides of an L-shape are: 4, 1, 3, 3, 1, and 4.
What are its area and perimeter?

4. a. Draw a square with a perimeter
of 4 inches. What is its area?

b. Draw a square with an area
of 9 cm². What is its perimeter?

5. If a rectangle's area is 24 square units, what can
its perimeter be? Fill in the table. You can sketch
rectangles in the grid.

Rectangle's sides	Area	Perimeter
4 and 6	24 sq. un.
	24 sq. un.
	24 sq. un.
	24 sq. un.

6. [available in the book]

7. If a rectangle's perimeter is 20, what can
its area be?

Rectangle's sides	Area	Perimeter
		20 units
		20 units
		20 units
		20 units
		20 units

8. a. Find the areas of the two parts A₁ and A₂.
b. Find the total area.
c. Find the perimeter.

9. [available in the book]

10. [available in the book]

11. Fill in. Draw a figure for each problem.

a. A rectangle with sides
4 units and _____ units;
area 20, perimeter______.

[available in the book]

12. A farmer wants to build a sheep yard that is 120 square feet in area.

a. Suggest three different rectangular shapes for him. Give their width and length.

b. Calculate how much fence he needs for each rectangle.
Which rectangular shape uses the least amount of fence?

13. [available in the book]

The ideas in this geometry lesson are taken from Math Mammoth Geometry 1 book.