A semicircular archway is built in front of a garden using 8 congruent granite tiles, as shown in the diagram. Find the area of one of the tiles. Round the answer to the nearest tenth.
A. 2.9ft^2
B. 5.9ft^2
C. 6.3ft^2
D. 12.6ft^2

(each tile is 1 ft in length, from the centre of the archway to the first tile is 7f. i tried to put in a picture but it wont let me)