Question

Triangle PQR has been dilated to form triangle P'Q'R'. What is the least amount of information needed to determine if the two triangles are similar?
A. Segments PR and P'R' are congruent, and segments QR and Q'R' are congruent.


B. Angle R=R', angle Q=Q', and segments QR and Q'R' are congruent.


C. Segment QR=Q'R', segment PR=P'R', and angles Q and Q' are congruent.


D. Angles Q and Q' are congruent, and angles R and R' are congruent.

Answer 1

For two triangles to be congruent, we need to show is two of the
1. corresponding angles are congruent,
or,
2. all three pairs of corresponding sides are proportional, 
or 
3. two pairs of corresponding sides are proportional AND the included angles are congruent.

Choice D saus, angles Q and Q' are congruent, angles R and R' are congruent, therefore satisfies the first criterion that at least two corresponding angles are congruent.

Answer 2

Angle Q and Q are congruent would be the correct answer