Answer:
93,431.4 feet.
Step-by-step explanation:
Let x represent distance between the plane and the arch.
We have been given that a plane flying within sight of the Gateway Arch in St. Louis, Missouri, at an elevation of 35,000 feet. The pilot finds that the angle of depression to a point on the ground below the arch is 22◦.
We can see from our attachment that plane, the gateway arch and angle of depression forms a right triangle with respect of ground.
The side with 35,000 ft is opposite side and side x is hypotenuse for 22 degree angle.
[tex]\text{sin}=\frac{\text{Opposite}}{\text{Hypotenuse}}[/tex]
[tex]\text{sin}(22^{\circ})=\frac{35,000}{x}[/tex]
[tex]x=\frac{35,000}{\text{sin}(22^{\circ})}[/tex]
[tex]x=\frac{35,000}{0.374606593416}[/tex]
[tex]x=93,431.350689[/tex]
[tex]x\approx 93,431.4[/tex]
Therefore, the distance between the plane and arc is 93,431.4 feet.