Answer:
32
Step-by-step explanation:
the equation of a right triangle is x^2 + y^2 = z^2, where x and y are the legs and z is the hypotenuse
write the equations for triangles QTS and STR:
RT^2 + TS^2 = 40^2
7^2 + TS^2 = 25^2
then solve for RT:
RT^2 - 7^2 = 40^2 - 25^2 (subtract second equation from first)
RT^2 = 1024
RT = 32
