Math Problem Statement

In the figure, BA and BC are opposite rays. BH bisects ∠EBC and BE bisects ∠ABF. If m∠ABF = (7b − 24)° and m∠ABE = 2b°, find m∠EBF.

Solution

The problem involves bisected angles, and we are given expressions for some of the angles.

Key Information:

  • BA\overrightarrow{BA} and BC\overrightarrow{BC} are opposite rays, meaning ABC\angle ABC forms a straight line (180°).
  • BH\overrightarrow{BH} bisects EBC\angle EBC, and BE\overrightarrow{BE} bisects ABF\angle ABF.
  • The measures of the angles are:
    • mABF=(7b24)m\angle ABF = (7b - 24)^\circ
    • mABE=2bm\angle ABE = 2b^\circ

We are tasked with finding mEBFm\angle EBF, which is half of ABF\angle ABF, because BE\overrightarrow{BE} bisects it.

Steps:

  1. Determine mABFm\angle ABF: mABF=(7b24)m\angle ABF = (7b - 24)^\circ

  2. Find mABEm\angle ABE: We are given mABE=2bm\angle ABE = 2b^\circ. Since BE\overrightarrow{BE} bisects ABF\angle ABF, it divides the angle into two equal parts: mABE+mEBF=mABFm\angle ABE + m\angle EBF = m\angle ABF

  3. Set up the equation: Using the fact that mABE=mEBFm\angle ABE = m\angle EBF: 2mABE=mABF2 \cdot m\angle ABE = m\angle ABF Substituting the known values: 2(2b)=7b242 \cdot (2b) = 7b - 24 Simplifying: 4b=7b244b = 7b - 24

  4. Solve for bb: 7b4b=247b - 4b = 24 3b=243b = 24 b=8b = 8

  5. Calculate mABFm\angle ABF: Substituting b=8b = 8 into the expression for mABFm\angle ABF: mABF=7(8)24=5624=32m\angle ABF = 7(8) - 24 = 56 - 24 = 32^\circ

  6. Find mEBFm\angle EBF: Since mABE=mEBFm\angle ABE = m\angle EBF and mABE=2bm\angle ABE = 2b, we substitute b=8b = 8: mEBF=2(8)=16m\angle EBF = 2(8) = 16^\circ

Final Answer:

mEBF=16m\angle EBF = 16^\circ.


Would you like more details or have any further questions? Here are some related questions:

  1. How do you determine if two rays are opposite?
  2. What does it mean for a ray to bisect an angle?
  3. How can you find the measure of angles in bisected geometric figures?
  4. What properties define angles formed by opposite rays?
  5. How can this technique be applied to other geometric bisectors?

Tip: When solving angle bisector problems, setting up an equation with known relationships can simplify finding unknowns.

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Math Problem Analysis

Mathematical Concepts

Geometry
Angle Bisectors
Linear Pair of Angles

Formulas

m∠ABF = (7b - 24)°
m∠ABE = 2b°
Sum of angles on a straight line = 180°

Theorems

Angle Bisector Theorem
Linear Pair Theorem

Suitable Grade Level

Grades 9-11