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Zorluk: OrtaTriangle Congruence, Similarity, and Theorems

In the figure below, ADAD is the angle bisector of BAC\angle BAC in triangle ABCABC. The length of segment ABAB is 2x2x, the length of segment ACAC is 3x33x-3, the length of segment BDBD is 66, and the length of segment CDCD is 88. What is the value of xx?

  1. A
    2
  2. B
    3
  3. C
    6
  4. 9Cevap

Cevap

The value of xx is 9.
According to the Angle Bisector Theorem, the bisector of an angle in a triangle divides the opposite side into segments that are proportional to the adjacent sides. This gives the proportion ABAC=BDCD\frac{AB}{AC} = \frac{BD}{CD}. Substituting the given values, we get 2x3x3=68\frac{2x}{3x-3} = \frac{6}{8}. Simplifying the right side to 34\frac{3}{4} and cross-multiplying yields 2x(4)=3(3x3)2x(4) = 3(3x-3), which simplifies to 8x=9x98x = 9x - 9. Solving for xx gives x=9x = 9.

Adım Adım Çözüm

1
Apply the Angle Bisector Theorem, which states that an angle bisector in a triangle divides the opposite side into two segments that are proportional to the other two sides.
ABAC=BDCD\frac{AB}{AC} = \frac{BD}{CD}
Because ADAD is the angle bisector of BAC\angle BAC, it splits BCBC at DD proportionally to the adjacent sides ABAB and ACAC.
2
Substitute the given side lengths into the proportion.
2x3x3=68\frac{2x}{3x-3} = \frac{6}{8}
To set up the algebraic equation for xx using the given lengths AB=2xAB = 2x, AC=3x3AC = 3x-3, BD=6BD = 6, and CD=8CD = 8.
3
Simplify the ratio on the right side of the equation and cross-multiply to solve for xx.
8x=9x98x = 9x - 9, which simplifies to x=9x = 9.
First simplify 68\frac{6}{8} to 34\frac{3}{4}, then cross-multiply: 2x(4)=3(3x3)2x(4) = 3(3x-3), which gives 8x=9x98x = 9x - 9. Subtracting 8x8x and adding 99 yields x=9x = 9.

Anahtar Kavram

Angle Bisector Theorem in Triangles
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