https://www.ridetech.com/info/wp-con.../04/dim-a2.gifhttps://www.ridetech.com/info/wp-con.../04/dim-b2.gif

Pics stolen from RideTechs website.

In the example I gave, the motion ratio is .646 for RideTechs c10 control arms. That number is the distance from spring mount to the inner control arm pivot divided by the distance from the ball joint to the inner control arm pivot.

Referencing the pics A ÷ B = MR