interpolation is one of the simplest ways of interpolation. Linear
interpolation determines, from two points (x1,y1) and
(x2,y2), what the value of y is at a different point x3.
Linear interpolation assumes a linear slope between points 1 and 2 and based
on that slope will determine what the value of y would be at another given
point x. Obviously a limitation of this method is that it assumes a linear
slope, and thus if the parameters do not have a linear relationship the
value returned would be incorrect.