Answer: "Similar by AA~"
Explanation:
We know there are 180 degrees in a triangle. We can use this knowledge to find the missing angle in each triangle. This is angle R and angle S.
180 - (100 + 45) = R∠35°
180 - (100 + 35) = S∠45°
Now, we can say that the triangles are similar by AA because the triangles have at least two corresponding congruent angles.