5.3. Angle Bisectors in Triangles http://www.ck12.org
Vocabulary
Anangle bisectorcuts an angle exactly in half.Equidistantmeans the same distance from. A point is equidistant
from two lines if it is the same distance from both lines. When we construct angle bisectors for the angles of a
triangle, they meet in one point. This point is called theincenterof the triangle.
Guided Practice
- Is there enough information to determine if
−→
ABis the angle bisector of^6 CAD? Why or why not?2.
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MOis the angle bisector of^6 LMN. Find the measure ofx.- A 100◦angle is bisected. What are the measures of the resulting angles?
Answers:
- No becauseBis not necessarily equidistant fromACandAD. We do not know if the angles in the diagram are
right angles.
2.LO=ONby the Angle Bisector Theorem.
4 x− 5 = 23
4 x= 28
x= 7