Interpolation + extrapolation matrix

I would like to resolve X,Y values matrix with another X,Y matrix. Values must be interpolate or extrapolate based on the new X,Y coordinates. Example (see attachment) : double[] X = new double[] { 93.40, 88.83, 84.26, 79.69, 75.12, 70.55, 65.98, 61.41, 56.84, 52.27, 47.70, 43.13, 38.56, 33.99, 29.42, 24.85, 20.28, 15.71, 11.14, 6.57 }; double[] Y = new double[] { 7.87, 12.56, 19.56, 26.56, 33.56, 48.56, 63.56, 78.56, 93.56, 108.56, 123.56, 138.56, 153.56, 168.56, 183.56, 198.56, 213.56, 228.56, 243.56, 258.56, 273.56, 288.56, 303.56, 318.56, 333.56, 348.56, 363.56, 378.56 }; double[,] XYvalues = new double[,] {{18.32,18.71,19.10,19.49,19.88,20.27,20.66,21.05,21.44,21.83,22.22,22.61,21.99,21.37,20.75,20.13,19.51,18.89,18.27,17.65} . . . } double[] newX = new double[] {85,80.00,75.00,70.00,65.00,60.00,55.00,50.00,45.00,40.00,35.00,30.00,25.00,20.00,15.00} double[] newY = new double[] {3,7,14,21,30,45,60,75,90,120,150,180,210,240,270,300,330,360} public double[,] resolveMatrixFromMatrix(double[] originalX, double[] originalY, double[,] originalValues, double[] newX, double[] newY ) { // . . . } public double resolveDataPointFromMatrix(double[] originalX, double[] originalY, double[,] originalValues, double newX, double newY) { // . . . } I think it's relatively quick for Matrix developer in C#. Thanks