@code {
// declare properties
private pageModel pm = new();
private EditContext? editContext;
private string message = "";
private string transformHour = "";
private string transformMinute = "";

// execute these elements when page is rendered
protected override void OnInitialized()
{
    // the model object that holds the data being edited, for example as a set of properties
    editContext = new EditContext(pm);

    // call and execute the HandleSubmit method.
    HandleSubmit();
}

private void HandleSubmit()
{
    try
    {
        if (editContext!.Validate())
        {
            // call the GetAngle helper method
            var angle = GetAngle(pm.hour, pm.minute);

            // create the message to show in the page
            // alternative: message = $"The angle between the hour and minute hands is {angle} degrees.";
            message = angle.ToString();
        }
    }
    // handle any errors that may occur
    catch (Exception ex)
    {
        message = ex.Message;
    }
}

// this method is the algoritym that calculates the angle
private decimal GetAngle(int hour, int minute)
{
    if (hour < 0 || hour > 23 || minute < 0 || minute > 59)
    {
        throw new ArgumentException("Invalid time entered.");
    }

    //convert 24 hour to 12 hour time
    if (hour > 11)
    {
        hour = hour - 12;
    }


    // The minute hand moves 6 degrees each minute:  360/60 = 6
    var minuteAngle = minute * 6;

    // The hour hand moves 30 degrees each hour: 360/12 = 30
    // The hour hand moves an addtional 6 degrees for
    //     each addtional minute past the hour.
    var hourAngle = (hour * 30) + (minuteAngle / 12);

    // return the angle between hour and minute hands
    var angle = Math.Abs(hourAngle - minuteAngle);

    //return the inside angle
    if (angle > 180)
    {
        angle = 360 - angle;
    }

    SetClockHands(hourAngle, minuteAngle);

    return angle;
}

// this method draws the clock hands to the time input in the page.
private void SetClockHands(int hDeg, int mDeg)
{
    transformHour = $"transform: rotate({hDeg + 90}deg);";
    transformMinute = $"transform: rotate({mDeg + 90}deg);";
}

// the model
public class pageModel()
{
    [Required]
    [Range(0, 23, ErrorMessage = "Hour must be between 0 and 23.")]
    public int hour { get; set; } = 3;

    [Required]
    [Range(0, 59, ErrorMessage = "Minute must be between 0 and 59.")]
    public int minute { get; set; } = 30;

}

This code is structured using .NET Razor Pages, which will include the Model, View and Controller actions all on one page. Only the code portion is displayed here for brevity.

The first thing done was to create the global properties. The first "OnInitialized()" method will instantiate an object for our model.

The next "HandleSubmit()" method retrieves the data from the form and passes the values into the "GetAngle()" method. I used a try/catch block to gracefully handle any errors.

The "GetAngle()" method holds the algorythm that calculates the inner angle between the hour and minute hands. It basically converts the minutes and hours into degrees, then takes the angle between 0 or 12 noon and the position of each hand on the clock. It subracts the two to get the angle between the hands, then subtracts 360 degrees if the angle is greater than 180 degrees to get the inside or acute angle.

Finally the "SetClockHands()" method redraws the hands of the clock image to represent the time entered in the form.

Please contact me if you have any questions and/or would like to discuss my skill set and qualifications.