The triangles PRQ and MRN are not similar.
Similar triangles:
Triangles are similar if their corresponding angles are congruent and the corresponding sides are in proportion.
This means the ratio of there corresponding sides must be equal. The corresponding angles must be the same . Therefore, the following rules must apply:
∠R = ∠R
∠Q = ∠N
∠P = ∠M
The following proportion rule must apply below:
PR / MR = RQ / RN = PQ / MN
18 / 10 = 21 / 7
9 : 5 ≠ 3 : 1
Therefore, the triangles are not similar
learn more on similar triangles here: https://brainly.com/question/10810713