we know that
in a right triangle
sin ∅=opposite side angle ∅/hypotenuse
opposite side angle ∅=hypotenuse*sin ∅
in this problem
angle ∅=48°
hypotenuse=100 ft
opposite side angle ∅=?----> height of the kite from the ground
opposite side angle ∅=100*sin 48°------> 74.31 ft
the answer is
74.31 ft