vb.net multi dimensional arrays - vb.net

Question

net right now regarding multi dimensional array my problem is i want to get the nearest numbers for example my input was 13000, the nearest number will be 11667 and then it will subtract it by 13000, then it will multiply by 0.25 and add my 1875.00. here is my code about multidimensional array can you please help me regarding this? i need this in my project thank you in advance
If ComboBox5.Text = "Z" Then
Dim zero(3, 8) As Double
Dim row As Double
Dim col As Double
'col 1
zero(0, 0) = 0.0
zero(1, 0) = 0
zero(2, 0) = 1
'col 2
zero(0, 1) = 0.0
zero(1, 1) = 0.05
zero(2, 1) = 0
'col 3
zero(0, 2) = 41.67
zero(1, 2) = 0.1
zero(2, 2) = 833
'col 4
zero(0, 3) = 208.33
zero(1, 3) = 0.15
zero(2, 3) = 2500
'col 5
zero(0, 4) = 708.33
zero(1, 4) = 0.2
zero(2, 4) = 5833
'col 6
zero(0, 5) = 1875.0
zero(1, 5) = 0.25
zero(2, 5) = 11667
'col 7
zero(0, 6) = 4166.67
zero(1, 6) = 0.3
zero(2, 6) = 20833
'col 8
zero(0, 7) = 10416.67
zero(1, 7) = 0.32
zero(2, 7) = 41667
For row = 0 To 3
For col = 0 To 8
If Val(TextBox18.Text) > Val(zero(row, col)) And Val(TextBox18.Text) < Val(zero(row - 1, col + 1)) Then
ListView1.Items.Add(zero(row, col))
End If
Next
Next
End If

Answer 1

2D array is not very appropriate to store this kind of data, but here is an example to get you started:
Dim data(,) = {
{0.0, 0, 1},
{0.0, 0.05, 0},
{41.67, 0.1, 833},
{208.33, 0.15, 2500},
{708.33, 0.2, 5833},
{1875.0, 0.25, 11667},
{4166.67, 0.3, 20833},
{10416.67, 0.32, 41667}}
Dim value = 13000 ' Dim value = Val(TextBox18.Text)
' data.GetLength(0) is 8, so Enumerable.Range generates the numbers from 0 to 7
Dim range = Enumerable.Range(0, data.GetLength(0))
' .OrderBy orders them by the difference between value and the last column in data
Dim ordered = range.OrderBy(Function(i) Math.Abs(data(i, 2) - value)) ' 5,4,6,3,2,0,1,7
Dim nearestIndex = ordered.First ' 5
Dim value1 = data(nearestIndex, 0) ' 1875.0
Dim value2 = data(nearestIndex, 1) ' 0.25
Dim value3 = data(nearestIndex, 2) ' 11667
Dim result = (value3 - value) * value2 + value1 ' result = 1541.75