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Example 1:
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Find the area of an
acute triangle
with a base of 15 inches and a height of 4 inches.
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![[IMAGE]](images/acute_triangle.gif)
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Solution:
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 =  · (15 in) · (4 in)
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= · (60 in2)
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= 30 in2
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Example 2:
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Find the area of a
right triangle
with a base of 6 centimeters and a height of 9 centimeters.
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![[IMAGE]](images/right_triangle_6x9.gif)
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Solution:
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= · (6 cm) · (9 cm)
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= · (54 cm2)
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= 27 cm2
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Example 3:
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Find the area of an
obtuse triangle
with a base of 5 inches and a height of 8 inches.
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![[IMAGE]](images/obtuse_triangle.gif)
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Solution:
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= · (5 in) · (8 in)
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= · (40 in2)
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= 20 in2
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Example 4:
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The area of a triangular-shaped mat is 18 square feet and the base is 3 feet. Find the height.
(Note: The triangle in the illustration to the right is NOT drawn to scale.)
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Solution:
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In this example, we are given the area of a triangle and one dimension, and we are asked to work
backwards to find the other dimension.
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18 ft2 = ·
(3 ft) · 
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Multiplying both sides of the equation by 2, we get:
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36 ft2 = (3 ft) ·
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Dividing both sides of the equation by 3 ft, we get:
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12 ft =
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Commuting this equation, we get:
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= 12 ft
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| Summary: |
Given the base and the height of a triangle, we can find the area. Given the area
and either the base or the height of a triangle, we can find the other dimension.
The formula for area of a triangle is:
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![[IMAGE]](images/intro_triangle.gif)
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or
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where  is the base,
is the height
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Interactive Math Goodies Software
