Question

Question is in image In the diagram below, ST is parallel to PR

Answer 1

Answer:

  D.

Step-by-step explanation:

There is nothing in the figure to indicate the triangles are isosceles. This eliminates answer choices A, B, C.

Answer choice D is a required step in the proof, but only gets part of the way. The triangle similarity means ...

  SQ/PQ = TQ/RQ

From here, you need to decompose each of the sides PQ and RQ into parts. Then you can get to the desired relationship.

  (PQ -PS)/PQ = (RQ -RT)/RQ . . . segment sum theorem

  1 - PS/PQ = 1 -RT/RQ . . . . . . . do the division

  -PS/PQ = -RT/RQ . . . . . . . . subtract 1 (subtraction property of equality)

  PS/PQ = RT/RQ . . . . . . . . multiply by -1 (multiplication property of equality)