Method 1:
(((11.0833^2)÷(4 x 2.667)) + 2.667) ÷ 2 =7.0908837125
Method 2:
(r – 2.667)^2 + (5.541)^2 = r^2
((-2.667)^2 + (5.541)^2) ÷ (2 x 2.667) = 7.089533
Method 3 ask wolframalpha
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Answer = 7.09057
Method 4
(2.667 ÷ 2) + ((11.083^2) ÷(8 x 2.667)) = 7.09057 feet (7'1").
Note that you should be able to verify the diameter of 14.18 feet (14'2") by holding a tape measure at one side of the circle and moving the other side until you find the farthest spot on the opposite side.