A person standing on the edge of a high cliff throws a rock straight up with initial speed 8.73 m/s. The rock misses the edge of the cliff as it falls back to earth. Assume the rock lands with a speed of 90.81 m/s, at the bottom of the valley below the cliff. What is the distance from where the person standing, to where the rock lands at the bottom of the valley below the cliff, in unit of meters? Neglecting the effects of air resistance. Use g=9.8 m/s.