Area

1
Area

• Measure of the space inside a given 2 dimensional
  area

2
CAHSEE Measurement and Geometry
MG 2.1 Use formulas routinely for finding the
perimeter and area of basic two-dimensional
figures and the surface area and volume of basic
three-dimensional figures including rectangles,
parallelograms, trapezoids, squares, triangles,
prisms, and cylinders. 3 questions
3
Area How many square units make up the inside of
the object?
2 cm
3 ft
5 in
4 cm
3 ft
4 in
Area 10 in2
Area 9 ft2
Area 8 cm2
Area measures the space in two dimensions.
4
Area of a Square or Rectangle
Area (length)(width) A l w
2 cm
3 ft
4 cm
3 ft
A l w 2 4 Area 8 cm2
A l w 3 3 Area 9 ft2
5
Sample Test Problem 1

• One side of a square has a length of 1.5 feet.
  What is the area of the square?
• 2.25 ft2
• 2.50 ft2
• 3 ft2
• 6 ft2

Area (length)(width) A l w 1.5 1.5
2.25 ft2 Answer a
6
Sample Test Problem 2

• Juan is going to put new carpet in the upstairs
  bedroom. The room is 10 feet by 15 feet. How much
  carpet will he need to purchase for this room?
• 25 ft2
• 50 ft2
• 150 ft2
• 325 ft2

Area (length)(width) A l w 10 15
150 ft2 Answer c
7
Area of a Parallelogram
Area (base)(height) A b h 7 4
28 in2
4 in
7 in
Area (base)(height) A b h 6 8
48 cm2
6 cm
8 cm
8
Sample Test Problem 3

• Which parallelogram has an area of 10 square
  centimeters?
• Base 5 Height 5
• Base 2 Height 5
• Base 20 Height 2
• Base 15 Height 5

Area (base)(height) A b h 2 5
10 cm2 Answer b
9
Area of a Triangle
Area ½ (base)(height) A ½ (b)(h)
5 in
3 m
4 in
7 m
A ½ (b)(h) ½ (4)(5) Area 10 in2
A ½ (b)(h) ½ (7)(3) 10.5 m2
10
Sample Test Problem 4

• What is the area of the figure below?
• 32 m2
• 48 m2
• 96 m2
• 160 m2

A ½ (b)(h) ½ (16)(6) 48 m2
10 m
6 m
16 m
11
Area of a Trapezoid
Area Area ½ (b1)(h) ½(b2)(h) Area
½ (b1b2)h
b2
2
h
1
b1
12
Trapezoid
10 cm
3mm
8mm
4 cm
2mm
6 cm
Area ½ (b1b2)h ½ (38)2
½ (11)(2) Area 11 mm2
Area ½ (b1b2)h ½ (10 6)4
½ (16)(4) Area 32 cm2
13
Sample Problem 5

• What is the area of the figure below?
• 16.5 in2
• 23.5 in2
• 42 in2
• 63 in2

Area ½ (b1b2)h ½ (7 4)3
½ (11)(3) Area 16.5 in2 Answer a
7 in
3 in
5 in
4.5 in
4 in
14
Area of a Circle
Area Pi radius2
radius

Pi ( ) ratio of the circumference of a circle
to its diameter approximate value 3.14 radius
( r ) - measure from center of a circle to any
side
15
Circle
Area (Pi)(radius)2
5 cm
cm2
16
Sample Problem 6

• What is the approximate area of a circle that has
  a radius of 6 millimeters?
• 9.14 mm2
• 18.84 mm2
• 37.68 mm2
• 113.04 mm2

Answer d
17
Sample Problem 7

• What is the approximate area of the circle below?
• 23.14 cm2
• 62.8 cm2
• 125.6 cm2
• 314 cm2

20 cm
Answer d
18
Other Resources

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• Frequently Asked Questions
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