Congruent Triangles 4-2B

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Congruent Triangles 4-2B

• What are the four short cuts to prove triangles
  congruent?

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Congruent Triangles

• Do you really need six pairs of corresponding
  congruent parts to prove triangles congruent?
• Look at the triangle.
• What angle is opposite side ST?
• What angle is included between RS and ST?

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What do you need to know?

• 1.Draw a triangle with sides 3 cm and 4 cm and an
  included angle of 45. Compare your triangle to
  a neighbors.
• 2. Draw a new triangle with angle measures of 40
  and 80 and an included side of 5 cm. Compare
  your triangle to a neighbors.
• 3. Draw a new triangle with angle measures of
  30, 50 and a side opposite of one of the angles
  of 6 cm. Compare your triangle.
• 4. Draw a new triangle with sides measuring 4cm,
  5cm, and 6cm. Compare your triangle.

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Side-Side-Side Congruence Postulate (SSS)

• If each of the three sides of one triangle are
  congruent to the side of another triangle, then
  the two triangles are congruent.

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Side-Angle-Side Congruence Postulate (SAS)

• If two sides and the included angle of one
  triangle are congruent to two sides and the
  included angle of another triangle, then the two
  triangles are congruent.

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Angle-Side-Angle Congruence Postulate (ASA)

• If two angles and the included side of one
  triangle are congruent to two angles and the
  included side of another triangle, then the two
  triangles are congruent.

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Side-Angle-Side Congruence Postulate (SAA)

• If two angles and a side opposite one of them in
  one triangle are congruent to the corresponding
  parts of another triangle, then the two triangles
  are congruent.

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Try It

• If possible, what is the congruence statement for
  this pair of triangles? If the triangles are not
  congruent, say so.

Needs more information
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Try It

• If possible, what is the congruence statement for
  this pair of triangles? If the triangles are not
  congruent, say so.

R
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• What are the four short
• cuts to prove triangles
• congruent?
• Side-Side-Side (SSS)
• Side-Angle-Side (SAS)
• Angle-Side-Angle (ASA)
• Side-Angle-Angle (SAA)

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Assignment 4-2B

• Page 263, 1-13, 21-25