Please answer soon!! Quadrilateral Q is reflected over the x-axis to form Q' and then over the y-axis to form Q". What is tr measure of side ST?

Answer: ST = 10
Step-by-step explanation:
When we do a reflection over an axis, we always will have that the sides of the figure that face in the direction of the (0,0) and in the opposite direction, keep pointing in the same directions (but in other quadrants)
This means that the side that faces the point where the two axis intercept (the (0,0)) is always the same for all the quadrants (and the same works for the opposite side.)
So we will have that ST = 10