Math Problem Statement

BD bisects ∠ABC. Find m∠ABD, m∠CBD, and m∠ABC. Given m∠ABC = (2 − 16x)° and m∠ABD = (2x + 81)°.

Solution

To solve the given problem, we have the following information:

  • BDBD bisects ABC\angle ABC, meaning mABD=mCBDm\angle ABD = m\angle CBD.
  • mABC=(216x)m\angle ABC = (2 - 16x)^\circ.
  • mABD=(2x+81)m\angle ABD = (2x + 81)^\circ.

Since BDBD bisects ABC\angle ABC, the two angles ABD\angle ABD and CBD\angle CBD are equal, and their sum equals mABCm\angle ABC.

Step-by-step approach:

  1. Set up the equation: mABC=mABD+mCBDm\angle ABC = m\angle ABD + m\angle CBD Since mABD=mCBDm\angle ABD = m\angle CBD, we can write: mABC=2×mABDm\angle ABC = 2 \times m\angle ABD Substituting the expressions for mABCm\angle ABC and mABDm\angle ABD: (216x)=2×(2x+81)(2 - 16x) = 2 \times (2x + 81)

  2. Solve the equation: (216x)=2(2x+81)(2 - 16x) = 2(2x + 81) Simplifying the right side: 216x=4x+1622 - 16x = 4x + 162 Move all terms involving xx to one side and constants to the other: 16x4x=1622-16x - 4x = 162 - 2 20x=160-20x = 160 Solve for xx: x=8x = -8

  3. Find the angle measures:

    • mABD=2x+81=2(8)+81=16+81=65m\angle ABD = 2x + 81 = 2(-8) + 81 = -16 + 81 = 65^\circ
    • mCBD=mABD=65m\angle CBD = m\angle ABD = 65^\circ
    • mABC=216x=216(8)=2+128=130m\angle ABC = 2 - 16x = 2 - 16(-8) = 2 + 128 = 130^\circ

Final answers:

  • mABD=65m\angle ABD = 65^\circ
  • mCBD=65m\angle CBD = 65^\circ
  • mABC=130m\angle ABC = 130^\circ

Let me know if you would like more details or have any questions!

Here are 5 related questions to expand on the concept:

  1. How do we know that the angles ABD\angle ABD and CBD\angle CBD are equal?
  2. What is the geometric property of an angle bisector in a triangle?
  3. How would the solution change if BDBD was not a bisector?
  4. What happens if the sum of ABC\angle ABC is greater than 180° in a triangle?
  5. Can you find the exterior angle formed by extending ABAB?

Tip: When working with angle bisectors, always remember that it divides the angle into two equal parts!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Geometry
Angle Bisector Theorem

Formulas

m∠ABC = m∠ABD + m∠CBD
m∠ABC = 2 × m∠ABD
(2 - 16x) = 2 × (2x + 81)

Theorems

Angle Bisector Theorem

Suitable Grade Level

Grades 9-10