Math Problem Statement

In triangle ABC, AG is an angle bisector. m∠BAG = 4x + 5 and m∠CAG = 2x + 15. Find x, m∠BAG, and m∠CAB.

Solution

Problem Explanation:

In this problem, AG\overline{AG} is an angle bisector in ABC\triangle ABC. This means that mBAGm\angle BAG and mCAGm\angle CAG are equal in measure, and their sum will give mCABm\angle CAB.

The given expressions are:

  • mBAG=4x+5m\angle BAG = 4x + 5
  • mCAG=2x+15m\angle CAG = 2x + 15

Steps to Solve:

  1. Since AG\overline{AG} bisects CAB\angle CAB: mBAG=mCAGm\angle BAG = m\angle CAG Therefore: 4x+5=2x+154x + 5 = 2x + 15

  2. Solve for xx: Subtract 2x2x from both sides: 2x+5=152x + 5 = 15 Subtract 55 from both sides: 2x=102x = 10 Divide by 2: x=5x = 5

  3. Substitute x=5x = 5 back into the expressions for mBAGm\angle BAG and mCAGm\angle CAG:

    • mBAG=4x+5=4(5)+5=20+5=25m\angle BAG = 4x + 5 = 4(5) + 5 = 20 + 5 = 25^\circ
    • mCAG=2x+15=2(5)+15=10+15=25m\angle CAG = 2x + 15 = 2(5) + 15 = 10 + 15 = 25^\circ
  4. Since AG\overline{AG} bisects CAB\angle CAB: mCAB=mBAG+mCAG=25+25=50m\angle CAB = m\angle BAG + m\angle CAG = 25^\circ + 25^\circ = 50^\circ

Final Answer:

  • x=5x = 5
  • mBAG=25m\angle BAG = 25^\circ
  • mCAB=50m\angle CAB = 50^\circ

Would you like further clarification or a detailed breakdown of any part?

Here are 5 related questions to expand your understanding:

  1. What are the properties of angle bisectors in a triangle?
  2. Can an angle bisector divide opposite sides proportionally in all triangles?
  3. How does this concept extend to finding unknown variables in other geometric figures?
  4. How is the Angle Bisector Theorem used differently from this direct angle equality method?
  5. Can AG\overline{AG} still be called an angle bisector if the triangle is not isosceles?

Tip: Always verify your final values by substituting back into the original equations to ensure consistency.

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Math Problem Analysis

Mathematical Concepts

Geometry
Algebra
Angle Bisectors

Formulas

Equality of angle measures for bisected angles
Substitution in expressions

Theorems

Angle Bisector Theorem

Suitable Grade Level

Grades 8-10