Explanation:
Terminal velocity is given by:
Here, m is the mass of the falling object, g is the gravitational acceleration, 
is the drag coefficient, 
is the fluid density through which the object is falling, and A is the projected area of the object. in this case the projected area is given by:
Recall that drag coefficient for a horizontal skydiver is equal to 1 and air density is 
.
Without drag contribution the motion of the person is an uniformly accelerated motion, thus:
If the desk doesn't move, then it's not accelerating.
If it's not accelerating, then the net force on it is zero.
If the net force on it is zero, then any forces on it are balanced.
If there are only two forces on it and they're balanced, then they have equal strengths, and they point in opposite directions.
So the friction on the desk must be equal to your<em> 245N</em> .
