Change 3d camera FOV based on player speed

If anyone could help me, that would be greatly appreciated, because for the life of me, i CANNOT figure out the math for this. and i can’t find anything on this. im making a 3d game in gdevelop, and i want to add an effect where the camera FOV changes based on the players current speed. when the player isn’t moving, the FOV is 45, when the player is at their top speed, the FOV should be 90. but i cannot figure this out. can anyone here help me out with the math here? im stuck.