Chapter 10 - Radical Expressions and Equations - 10-6 Trigonometric Ratios - Practice and Problem-Solving Exercises - Page 638: 38

2.705 feet

$tan (30) = 10/x$ $x*tan (30) = 10/x*x$ $x*tan (30) = 10$ $.577x = 10$ $.577x/.577 = 10/.577$ $x = 17.33$ $tan (40) = 10/x$ $tan (40)*x = 10/x*x$ $x* tan (40) = 10$ $x*tan (40)/tan (40) = 10/tan (40)$ $x = 10/tan (40)$ $x = 10/.839$ $x = 11.92$ $(17.33+11.92)/2$ $29.25/2$ $14.625$ $17.33-14.625$ $2.705$