Soru

Zorluk: KolayTriangle Congruence, Similarity, and Theorems

In the triangles PQRPQR and STUSTU shown, PS\angle P \cong \angle S and QT\angle Q \cong \angle T. If the length of PQPQ is 1010, the length of QRQR is 1515, and the length of STST is 66, what is the length of TUTU?

  1. A
    4
  2. 9Cevap
  3. C
    11
  4. D
    25

Cevap

9
Since two angles of triangle PQRPQR are congruent to two angles of triangle STUSTU, the triangles are similar by the Angle-Angle similarity theorem. Therefore, the ratio of corresponding side lengths is constant, which gives the equation PQST=QRTU\frac{PQ}{ST} = \frac{QR}{TU}. Substituting the given values yields 106=15TU\frac{10}{6} = \frac{15}{TU}. Solving for TUTU gives 10×TU=9010 \times TU = 90, which simplifies to TU=9TU = 9.

Adım Adım Çözüm

1
Identify the relationship between the two triangles.
The triangles are similar (PQRSTU\triangle PQR \sim \triangle STU).
Since two angles of triangle PQRPQR are congruent to two angles of triangle STUSTU, the triangles are similar by the Angle-Angle (AA) similarity theorem.
2
Set up a proportion using corresponding side lengths.
PQST=QRTU\frac{PQ}{ST} = \frac{QR}{TU}
Corresponding sides of similar triangles are proportional.
3
Substitute the known values and solve for the unknown side length.
TU=9TU = 9
Substituting the values gives 106=15TU\frac{10}{6} = \frac{15}{TU}. Cross-multiplying yields 10×TU=9010 \times TU = 90, which simplifies to TU=9TU = 9.

Anahtar Kavram

Triangle Similarity (AA Postulate)

Alternatif Yöntem

Find the scale factor from triangle PQRPQR to triangle STUSTU, which is STPQ=610=0.6\frac{ST}{PQ} = \frac{6}{10} = 0.6. Then, multiply the corresponding side QRQR by this scale factor: 15×0.6=915 \times 0.6 = 9.
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