a kit has 25 feet of string.The wind is blowing to the west so that the angle of elevation is 40 degrees. how far has the kite traveled hori

The horizontal distance, d, is the adjacent side of a triangle of which the kite length is the hypotenuse, so 

cos(40°) = d/25

Multiply both sides by 25

d = 25*cos(40°) feet

$${\mathtt{d}} = {\mathtt{25}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{40}}^\circ\right)} \Rightarrow {\mathtt{d}} = {\mathtt{19.151\: \!111\: \!077\: \!975}}$$

d ≈ 19.15 feet