Like what you saw?
Create FREE Account and:
- Watch all FREE content in 21 subjects(388 videos for 23 hours)
- FREE advice on how to get better grades at school from an expert
- Attend and watch FREE live webinar on useful topics
Angle Bisectors - ConceptFREE
Univ. of Wisconsin
J.D. Univ. of Wisconsin Law school
Brian was a geometry teacher through the Teach for America program and started the geometry program at his school
An angle is formed by two rays with a common endpoint. The angle bisector is a ray or line segment that bisects the angle, creating two congruent angles. To construct an angle bisector you need a compass and straightedge. Bisectors are very important in identifying corresponding parts of similar triangles and in solving proofs.
In a triangle if you draw in one of your angle bisectors, remember there's three, one for each vertex, you're going to divide the opposite side proportionally. Well, we could write two different ratios here and I'm going to explain what I mean by opposite side. If I look at this as my vertex and I'm bisecting it the side that's opposite to it, is going to be that opposite side the one that contains x and y here.
So I can say that the ratio of a:x so I'm going to write the ratio of a:x has to be equal to the ratio of b:y. Another way of looking at it is what's the relationship between a and b. I can say that a goes to b the way x goes to y.
So when you homework around a test you're going to see a problem where you have a triangle with an angle bisector and you're going to be trying to find some of these missing lengths. Remember that it will divide this opposite side proportionally.
Stuck on a Math Problem?
Ask Genie for a step-by-step solution
Please enter your name.
Are you sure you want to delete this comment?
- Using a Protractor 20,619 views
- Supplementary and Complementary Angles 24,917 views
- Polygons 16,890 views
- Types of Triangles 20,250 views
- Perimeter 11,431 views
- Parts of a Circle 14,292 views
- Three Undefined Terms: Point, Line, and Plane 64,924 views
- Counterexample 27,371 views
- Writing a Good Definition 17,455 views
- Postulate, Axiom, Conjecture 19,417 views
- Converse 14,991 views
- Line Segments 33,823 views
- Rays 24,310 views
- Parallel and Skew Lines 31,320 views
- Midpoints and Congruent Segments 25,296 views
- Parallel Planes and Lines 23,173 views
- Vertex and Diagonals 15,785 views
- Calculating the Midpoint 20,755 views
- Angles: Types and Labeling 24,065 views