Math Problem Statement

BD bisects ∠ABC. Find m∠ABD, m∠CBD, and m∠ABC, given that ∠ABD = 8x + 35° and ∠CBD = 11x + 23°.

Solution

We are given that BDBD bisects ABC\angle ABC, meaning that ABD=CBD\angle ABD = \angle CBD. Also, we have the expressions for the two angles:

ABD=8x+35andCBD=11x+23.\angle ABD = 8x + 35^\circ \quad \text{and} \quad \angle CBD = 11x + 23^\circ.

Since BDBD bisects ABC\angle ABC, we have:

8x+35=11x+23.8x + 35^\circ = 11x + 23^\circ.

Let's solve for xx:

8x+35=11x+23.8x + 35 = 11x + 23.

Subtract 8x8x from both sides:

35=3x+23.35 = 3x + 23.

Subtract 23 from both sides:

12=3x.12 = 3x.

Now, divide by 3:

x=4.x = 4.

Now that we have x=4x = 4, we can substitute this value back into the expressions for ABD\angle ABD and CBD\angle CBD.

  1. ABD=8(4)+35=32+35=67\angle ABD = 8(4) + 35 = 32 + 35 = 67^\circ.
  2. CBD=11(4)+23=44+23=67\angle CBD = 11(4) + 23 = 44 + 23 = 67^\circ.

Since BDBD bisects ABC\angle ABC, the full angle ABC\angle ABC is the sum of ABD\angle ABD and CBD\angle CBD:

ABC=67+67=134.\angle ABC = 67^\circ + 67^\circ = 134^\circ.

Final answers:

  • mABD=67m\angle ABD = 67^\circ
  • mCBD=67m\angle CBD = 67^\circ
  • mABC=134m\angle ABC = 134^\circ

Would you like a detailed breakdown of the steps? Here are some additional questions to consider:

  1. How do we verify that BDBD bisects ABC\angle ABC?
  2. What are the implications of angle bisectors in triangles?
  3. How can we apply this method to different geometric problems involving bisectors?
  4. What if BDBD did not bisect ABC\angle ABC, how would the solution change?
  5. How do we find the external angles related to this problem?

Tip: In problems involving bisectors, always remember that the bisector divides an angle into two equal parts, which can simplify solving for unknowns.

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Math Problem Analysis

Mathematical Concepts

Algebra
Angle Bisectors
Geometry

Formulas

8x + 35° = 11x + 23°
m∠ABC = m∠ABD + m∠CBD

Theorems

Angle Bisector Theorem

Suitable Grade Level

Grades 8-10