Let the mouse start at point 0, and making the final point x = 3.5 + 5.0*cos(-45) = 7.04m y = 0 + 5.0*sin(-45) = -3.54m z = -1.0m
This makes the final point equal to (7.04, -3.54, -1.0)m
And the net displacement is:d = sqrt(x^2 + y^2 + z^2) 7.9m = sqrt( 7.04^2 + 3.54^2 + 1.0^2)
Answer is 7.9m