a basebasll diamond is a square with side 90 ft 90 ft . a batter hits the ball and runs toward first base with a speed of 21 ft/s 21 ft/s . (a) at what rate is his distance from second base decreasing when he is halfway to first base? (round your answer to one decimal place.) ft/s ft/s (b) at what rate is his distance from third base increasing at the same moment? (round your answer to one decimal place.) ft/s ft/s