Answer:
60degrees
Step-by-step explanation:
For similar triangles, the angles of their angles are equal to matter the size.
Hence if triangle TRS is similar to triangle TMN, then;
<R = <M and <S = <N
Given that;
<T = 40 degrees
<R = 60degrees
<S = 80 degrees
Since <R = <M, then <M = 60degrees
