23o29' = 29.483o
I can't draw the triangle well on this editor, but it looks
kind of like this:
23o29' angle | height
The line from Bob to the Peak of the mountain is the hypotenuse, and Bob's distance from the center base of the mountain is one leg, and the height of the mountain is the other leg. The 23o29' angle is between the hypotenuse and the leg from Bob to the Base (16194.6 ft). The side opposite to the angle is the height of the mountain.
The relevant trig function, then, is the tangent:
Tangent x = opposite side/adjacent side
Here the adjacent side is 16,194.6 feet and the opposite side is the height of the mountain. So
Tan(23.483o) = height/(16,194.6)
Solve for the height.