[DotNetDevelopment] web service problem

[Brock]

I have a Web service I created for doing math conversions (in this
case the partial volume of a sphere). I'm seeing a conflict with the
Web service method and the code-behind on my .aspx page that consumes
the service. Does anyone see anything wrong with the
code?:                        THANKS!!!  (btw... this is not a
homework assignment)

Web service side (no compiler errors):

    <System.Web.Services.WebMethod()> _
Public Function PartialSphereVolume(ByVal Radius As Double, ByVal
Height As Double) As Double
        Return ((Radius * Math.PI * (Height ^ 2)) - (Math.PI *
((Height ^ 3) / 3)))
    End Function

.aspx Consuming side (compile error is in the
"wsConvert.PartialSphereVolume(partialvolume)" phrase:

    Protected Sub btnSpherePartialVolume_Click(ByVal sender As Object,
ByVal e As System.EventArgs) Handles btnSpherePartialVolume.Click
        Dim wsConvert As New com.mysite.SphericalVolumeWebService
        Dim partialvolume As Double
        partialvolume = System.Convert.ToDouble(txtRadius3.Text)
        partialvolume = System.Convert.ToDouble(txtHeight.Text)
        System.Threading.Thread.Sleep(3000)
        lblSphericalPartialVolume.Text = wsConvert.PartialSphereVolume
(partialvolume).ToString("#,##0.00")
    End Sub