(a) The hour hand moves 360° in 12 hours, so 30° per hour. The angle is
... arccos(-.7071) = 225°
so, the time is 225/30 hours = 7 1/2 hours past midnight. The time is 7:30 a.m.
(b) The ratio of the adjacent distance to the hypotenuse is given by the cosine of the angle. For your angle, the adjacent distance is the distance you want to find, so it is found as
... (10 cm)×(-0.7071) = -7.071 cm
The tip of the hand is 7.071 cm below the horizontal.
