Answer:
60
Step-by-step explanation:
The measure of ∠ATS is 120. The measure of a straight angle is always going to be 180 degrees. So first, we subtract 120 from 180 to find the measure of the interior angle.
∠STR = 180 - 120
= 60
The measure of all the interior angles in the triangle ΔSTR is 180 degrees.
180 - 60 - 60
= 60
The measure of ∠TSR is 60 degrees.
