Consider a right triangle with sides of length x and y, a hypotenuse of length r, and an interior angle theta, such that tan(theta) = y/x. To an observer moving parallel to side x with speed v, the triangle has sides of length x' and y', a hypotenuse of length r', and an interior angle "theta prime".
(a) Does the moving observer see it as a right triangle? Explain.
(b) Find an expression for the angle "theta prime" in terms of theta and v.
(c) Find an expression for r' in terms of r, v, and theta.