Final answer:
To find the length of side s in ΔRST, we can use the Law of Cosines. By substituting the given values into the equation, we can solve for s.
Step-by-step explanation:
To find the length of side s in ΔRST, we can use the Law of Cosines which states that c^2 = a^2 + b^2 - 2abcos(C).
In this case, s is the side opposite angle S, so we can write the equation as
s^2 = r^2 + t^2 - 2rtcos(S).
Substituting the given values into the equation, we get
s^2 = 40^2 + 20^2 - 2(40)(20)cos(55°).
Solving this equation, we find s ≈ 17 inches.