9514 1404 393
Answer:
(C) SAS
Step-by-step explanation:
The obtuse angles in each triangle are "corresponding" with respect to the segments marked parallel and the horizontal transversal.
Those angles are between pairs of proportional sides:
60/42 = 40/28 = 10/7
so, the applicable theorem is SAS. The triangles can be proven similar using the SAS theorem.
