Linear interpolation

Using linear interpolation, given any two points

(x₀, y₀) and (x₁, y₁)

and the value x₂,where x₀≤x₂ ≤x₁

the corresponding y₂ value is given by

y2 = y0 + (y1-y0) / (x1-x0) * (x2-x0)

    var x0 = 1;
    var x1 = 20;
    var y0 = 30;
    var y1 = 35;
    var arr = new Array();
	
    for (i=1;i<=20;i++){
        y2 = y0 + (y1-y0) / (x1-x0) * (i-x0)
        arr[i] = i+' ...... '+y2;
    }

view demo