The plane was 4 miles from laguardia airport and was ascending at an angle of 7.7 degrees. calculate the planes height above ground level at the time of the bird strike

The picture in the attached figure

Let 
h-------> the planes height above ground level at the time of the bird strike

we know that
sin 7.7°=opposite side angle 7.7°/hypotenuse
where
opposite side angle 7.7°=h
hypotenuse=4 miles
so
sin 7.7°=h/4-------> h=4*sin 7.7°-----> h=0.54 miles

1 mile-----------> 5280 ft
0.54 mile------> x
x=0.54*5280-----> x=2829.79 ft------> 2830 ft

the answer is
2830 ft