Respuesta :

DeanR

We have a right triangle hypotenuse 80 and adjacent angle 87°

So the short leg s is

s = 80 cos 87° =  4.19

rounded to two places.  So the height we seek is 7 - 4.19 or

Answer: 2.81 feet
2.813123501 ft

solution:

h/80=cos 87
h=80*cos87
x=7-(80*cos 87)
x=2.813123