Question 198204
Make a right triangle with leg of 30ft and opposite angle of 12.7deg

Solve for other leg
{{{tan(12.7)=(30/a)}}}
{{{a=(30/tan(12.7))}}}
{{{a=133.12049850724641310871629550339=133ft 1in}}}

Repeat with new angle of 14.5deg
{{{tan(14.5)=(30/a)}}}
{{{a=(30/tan(14.5))}}}
{{{a=116.0013928469621446992171095257=116ft 0in}}}

Subtract
{{{a[1]-a[2]=d}}}
{{{133-116=d}}}
{{{d=17ft}}}