TRIANGLES

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TRIANGLES

• (There are three sides to every story!)

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What kind of triangle has sides of 4 in. , 6 in.
and 3 in.?
SCALENE
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What kind of triangle has Angles of
90o, 70o, 20o.?
RIGHT
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What kind of triangle has sides of 5 in. , 5 in.
and 3 in.?
ISOSCELES
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What kind of triangle has Angles of
50o, 60o, 70o.?
ACUTE
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What kind of triangle has Angles of
60o, 60o, 60o.?
EQUIANGULAR
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What kind of triangle has Angles of
150o, 10o, 20o.?
OBTUSE
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What kind of triangle has sides of 5 in. , 5 in.
and 5 in.?
EQUILATERAL
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What kind of triangle has Angles of
150o, 160o, 170o.?
NO SUCH TRIANGLE
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What do we call the congruent sides of an
Isosceles Triangle?
The LEGS
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If D ABC has a right angle at B, which side is
the Hypotenuse?
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Which triangle is Impossible?

• EQUIANGULAR OBTUSE
• SCALENE ISOSCELES
• RIGHT EQUILATERAL

ALL THREE!!
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When referring to angle 5, what do we call
?
REMOTE INTERIOR ANGLES
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If this triangle is Equiangular
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If this triangle is Equiangular
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Set up the equation needed to solve the for x
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Set up the equation needed to solve for x
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(No Transcript)
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(No Transcript)
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Find AB (Use distance formula or Pythagorean
theorem)
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Find AC (Use distance formula or Pythagorean
theorem)
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Find BC (Use distance formula or Pythagorean
theorem)
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Recall AB5 AC5 BC 1.41 What kind of triangle
is it?
ISOSCELES
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PROVE The acute angles of a right triangle are
complementary.

• Given
• Definition of Right Triangle
• 3. Angle Sum Theorem
• Def. of Right Angle
• Substitution
• 6.
• 7.

Subtraction Prop of Eq.
Def. of Complementary
7.
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PROVE The measure of an exterior angle of a
triangle is equal to the sum of its remote
interior angles.
GIVEN The triangle pictured PROVE

• Given
• Angle Sum Theorem
• Supplement Theorem
• 4.
• 5.

1. The triangle pictured

Substitution
Subtraction Prop. Of Eq.
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The End