



 
Hi Richard. You can see the mathematical method I am using by reading http://mathcentral.uregina.ca/QQ/database/QQ.09.06/s/angela1.html The short answer (based on the notation in that web page) is:
So the radius r = 172.7 inches or about 14' 4.7". If you pick one side of the doorway and measure horizontally from there, you can determine the height that the arch should be above that location (in inches) by calculating:
where x is the horizontal distance from the side of the doorway and h is the height of the arch at that spot. All measurements in total inches. Hope this helps,  


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