We will use the cosine rule to find the measure of angle Q
The cosine rule is

RS = 15, QR = 13, QS = 12
Substitute them in the rule above

Subtract 313 from both sides

Divide both sides by - 312

Now we will find the value of the angle Q

Round it to the nearest tenth
The measure of angle Q is 73.6 degrees
First answer
You can consider it as 73.5 degrees