David drew PQR and STU so that P S, PR = 12, SU = 3, PQ = 20, and ST = 5. Are PQR and STU similar? If so, identify the similarity postulate or theorem that applies.

PR : PQ = 12 : 20 = 3 : 5

SU : ST = 3 : 5

and ∠ P = ∠ S

SAS: side, angle, side.

The triangles are similar if:

- the ratio between 2 sides of one triangle is the same as the ratio between 2 sides of another.

- the included angles are equal.

Triangles PQR and STU are similar.