Isosceles, Equilateral, and Right Triangles

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Isosceles, Equilateral, and Right Triangles

• Chapter 4.6

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Properties of Isosceles Triangles

• Legs- two congruent sides.
• Base- third side not congruent to any other side.
  
• Base angles- angles opposite of the legs.
• Vertex angle- angle opposite the base.

Vertex Angle
Base
Legs
Base angles
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Theorem 4.6Base Angles Theorem

• Two sides of a triangle are congruent iff the
  angles opposite them are congruent.

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Corollary to Base Angles Theorem

• A triangle is equiangular iff it is an
  equilateral triangle.

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Example
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Theorem 4.8 (HL) Hypotenuse-Leg Congruence
Theorem

• If the hypotenuse and a leg of a right triangle
  are congruent to the hypotenuse and a leg of a
  second right triangle, then the two triangles are
  congruent.

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Homework

• Pg. 239-241
• 8-10, 13, 14, 17-25, 33