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

Answer 1

angles Q and Q' are congruent, angles R and R' are congruent

Explanation:

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.

And, angles are always congruent when a figure is dilated

• Therefore, angles Q and Q' are congruent, angles R and R' are congruent

(satisfies the first criterion that at least two corresponding angles are congruent)