A motor-driven floor scrubber has a mass of 1.5 kg and a diameter of 430 mm. The scrubber rotates about an axle attached to its center. The scrubber sweeps an angle as a function of time given by θ(t) = At² + Bt⁴. If θ is in radians, t in seconds, and A and B are equal to 0.820 and 0.710, respectively, determine the units of A and B.