00:02
Okay, so let's draw a sketch and figure out this situation.
00:06
So we have the pilot flying the plane, and we have the angle of depression from the plane to the start of the airport runway.
00:14
So let's say this point down here is the start of the runway, and the angle of depression is the angle that's made with the horizontal, and you're looking down at something.
00:25
So try to make that line straight there.
00:27
So the angle of depression is this angle here, and that is one degree.
00:32
And we know the height of the airplane is 30 ,000 feet.
00:41
And what we're asked to find, i'll make a right angle symbol in the corner there.
00:45
We have a right triangle.
00:46
And what we're asked to find is the horizontal distance along the ground, which is the same as the horizontal distance of that side of the triangle up there from the plane to the runway.
00:57
So now that we have this information on a right triangle, what we can do is use a tangent ratio, the tangent of one.
01:05
Degree equals the opposite 30 ,000 over the adjacent x.
01:12
Now let's solve that equation for x...