If you would like to know how tall is the tower, you can calculate this using the following steps:
Miguel 5ft 10 inches = 70 inches tall ... 4ft 2 inches = 50 inches long shadow
tower x ft y inches = w inches high = ? ... 8ft 9 inches = 105 inches long shadow
70 * 105 = 50 * w /50
w = 70 * 105 / 50
w = 147 inches high = 12ft 3 inches
The correct result would be 12ft 3 inches.