Finding the smallest closest value in an array

Question

I have the code as below

    var searchValues = new double[] { 21.1, 21.65, 22.2, 22.75, 23.3, 23.85, 24.4, 24.95, 25.5, 26.05, 26.6, 27.15, 27.7, 28.25, 28.8