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Course: Geometry (all content) > Unit 12

Lesson 4: Angle bisector theorem
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Geometry (all content)
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Angle bisector theorem
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Solve triangles: angle bisector theorem

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Problem

∠DAC=∠BAD.
What is the length of CD―?
Round to one decimal place.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
Triangle A B C, but angle A is bisected by line segment A D, creating two new triangles, triangle A C D and triangle A B D. Point D is on Side B C. Side A C is five point nine units. Side D B is two point eight units. Side A B is eight point one units.