<TelerikArcGauge>
    <ArcGaugeCenterLabel>
        <Template>
            @(context.Pointers[0].Value)
        </Template>
    </ArcGaugeCenterLabel>
    <ArcGaugeScales>
        <ArcGaugeScale Min="0" Max="100">
        </ArcGaugeScale>
    </ArcGaugeScales>
    <ArcGaugePointers>
        <ArcGaugePointer Color="#FFE162" Value="@FirstPointerValue"></ArcGaugePointer>
    </ArcGaugePointers>
</TelerikArcGauge>

<TelerikTooltip TargetSelector="path[stroke='#FFE162']" Position="TooltipPosition.Top" ShowOn="@TooltipShowEvent.Hover" Id="first-pointer">
    <Template>
        <p>Value is: @FirstPointerValue</p>
    </Template>
</TelerikTooltip>

@code {
    public int FirstPointerValue { get; set; } = 20;
}