Page 673 - Basic College Mathematics with Early Integers

Objective 9.4 AREA

Find the Areas of Geometric
Figures.
Objective Finding Areas of Geometric Figures
Recall that area measures the amount of surface of a region.Thus far, we know how
to find the area of a rectangle and a square. These formulas, as well as formulas for
finding the areas of other common geometric figures, are given next:

Area Formulas of Common Geometric Figures
Geometric Figure Area Formula

RECTANGLE Area of a rectangle:
#
Area = length width
A = lw
width

length

SQUARE Area of a square:
#
Area = side side
A = s s = s 2
#
side

side

TRIANGLE Area of a triangle:
1
#
Area = # base height
2
height 1
A = bh
2
base
PARALLELOGRAM Area of a parallelogram:
#
Area = base height
A = bh
height

base
TRAPEZOID Area of a trapezoid:

one base or b 1
#
Area = # 1one base + other Base2 height
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2
height 1
A = 1b + B2h
2
other Base or B

Use these formulas for the following examples.
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