Verified answer

The skier is moving in two directions forward and down.

You can draw a triangle to symbolise this. The hypotenuse is 66 the 'overall' speed. Base is the 'forward' speed and the height how fast he/she is going down - this is what you want.

To find it simply use trig - 66 sine 69.0°

Which means the skier's altitude is decreasing by 61.62km/h

I say an object goes from point A to point B in some time. The first thing that comes to mind is this image. The object transverses the distance in a straight line. It could have very well taken a circular path, but that would take longer, but wait, what if it went faster to make up for the time difference? Then it would be impossible looking at the two frames to decide what path was taken. This is how time is. We can not experience absolute time, only finite segments. We do not know if time is like a DJ's record being scratched, because if it were, we would never know the difference. Interesting question.

speed = 66 km/h

Slope angle = 69.0°

Speed of Altitude = 66*sin(69.0°) = 61.6 km/h ........ answer