Automatic calculation by inputting value
Formula description
A method of using two known quantities in a linear trend to find another unknown quantity.

If two linear points are known (X1, Y1)=(1, 2), (X2, Y2)=(3, 4)
Find another unknown quantity (X, Y), when X=2, Y=?
(Y2-Y1)/(X2-X1)=(X-X1)/(Y-Y1)
(4-2)/(3-1)=(2-1)/(Y-2)
Y=3