Im trying to figure out how to find the height of the arc or maybe the distance between arc and line given than both of these lines/curves have exact same start and end points...the only difference is that the arc is curved and thus its longer than the straight line. I am attaching an image to better illustrate the problem.
Also, I used 3d modeling software to create an example and get actual numbers. So if you have L1, which is a straight line equal to 100cm and L2, the arc curve is 102.6 cm, then D = 10cm. What is the formula that I can apply to always find D given I know the lengths of L1 and L2. D is in the center (midpoint) of straight line and arc.
Thanks in advance!

