Show the average value of the chart like a circle in the bar chart

You can achieve this with the help of the donut chart in tableau. Just follow the below steps and get it done-

1. Drag the required dimension and measure in the row and column shelves
   
2. Make the chart type as a pie chart
   
3. Now add that measure again
   
4. Make it dual-axis
   
5. Again make that pie chart again
   

Now adjust the sizing and make the 2nd pie chart color as white. This is where you will add the number.