Converse to the Pythagorean Theorem

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Converse to the Pythagorean Theorem

• Ch 7.2

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Converse to the Pythagorean Theorem

• If the square of the length of the longest side
  of a triangle is equal to the sum of the squares
  of the lengths of the 2 other sides, then the
  triangle is a right triangle.

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Verifying that something is or is not a right
triangle.
1. First we determine which side would be the
hypotenuse.
2. Second we plug the values into the
Pythagorean theorem.
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Is it a right triangle?
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Theorem 7.3
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Theorem 7.4
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Classify the triangle as right, obtuse or acute.
15, 20, 25
9, 10, 15
right
8, 9, 10
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Graphing Triangles

1. When graphing triangles first plot the 3 points.
2. Decide on your method.
3. Find the slope and determine whether there are
   perpendicular lines. (Only works with right
   triangles)
4. Find the distance of each side of the triangle,
   then plug it back into the Pythagorean Theorem.

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Graphing Triangles
right
A (1, 5), B(1, 1), C(6, 1)
What kind of triangle is the graphed triangle?
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Graphing Triangles
A (2, 4), B(4, 1), C(7, 1)
What kind of triangle is the graphed triangle?
obtuse
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Graphing Triangles
What kind of triangle is the graphed triangle?
A (3, -2), B(1, 0), C(7, 2)
Find the distance of each side of the triangle
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Graphing Triangles
A (3, -2), B(1, 0), C(7, 2)
right
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Graphing triangles
A (-3, 5), B(0,-2), C(4, 1)
acute
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