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Triangle Congruence

Author:Heather O'Brien, Judith Hilinski

What does "congruent" triangles mean?

A congruent triangle means that one triangle shape can fit exactly over another using Turns, Flips and Slides
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Congruent Triangles
When two triangles are congruent they will have exactly the same side measures (all 3 sides), and the same angle measures (all 3 angles).The equal sides and angles may not be in the same position, but they are there.
Same Sides
When the sides are the same then the triangles are congruent.
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Same Angles
Does this also work with angles? Not always!
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Marking
When two triangles are congruent we often mark corresponding sides and angles like this:
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The sides marked with one line are equal in length. Similarly for the sides marked with two lines. Also for the sides marked with three lines. The angles marked with one arc are equal in size. Similarly for the angles marked with two arcs. Also for the angles marked with three arc.
Your Turn!
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Choose the correct answer

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)
Image

Choose the correct answer

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)
Image

Choose the correct answer

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)

Which one of the following statements is NOT sufficient to determine whether or not two triangles P and Q are congruent?

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)

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