Question 126·200 Super-Hard SAT Math Questions·Geometry and Trigonometry
In triangle , , , and . Point lies on segment such that bisects . Through , a line is drawn parallel to that intersects at . Аnікo.ai - SAT Рrеp
Which choice is the length of segment ?
When an angle bisector and a line parallel to a triangle side both appear, it usually signals a two-tool solution: (1) use the Angle Bisector Theorem to get the exact split of the opposite side, and (2) use the parallel line to establish similar triangles and a clean proportion. After you find the needed segment on a full side (like on ), double-check whether the question wants that segment or its complement (like ).
Hints
Split using the angle bisector
Since bisects , set up and use .
Look for similar triangles
Because is parallel to , triangle should be similar to triangle .
Use a scale factor from the side on
In the similar triangles, corresponds to , so the scale factor from big to small is .
Desmos Guide
Let represent and solve the angle-bisector ratio
Enter the two equations
Find their intersection. The -coordinate is .
Compute using similarity
Create an expression for using the similarity ratio :
CE = 14*x/12
Compute and match to a choice
Create AE = 14 - CE. The value shown for AE matches exactly one of the answer choices.
Step-by-step Explanation
Use the Angle Bisector Theorem
Because bisects , the Angle Bisector Theorem gives Written bу Аnікο
Also, . With ratio , the 12 units are split into and , so and .
Identify similar triangles using the parallel line
Since , angle equals angle and angle equals angle . Therefore, triangles and are similar.
Corresponding sides give
Substitute values:
Subtract to find
Points , , and are collinear with on , so .
Therefore, the correct choice is .