m e n - o c d a. Circles quadruple one to another, and here it is an eighth and a half. a b c is worth b c e, but because a b c is not capable of receiving into itself all of b c e, I lend it the triangle n m e, and lend as much to b c e, which is o, and thus the two surfaces are made equal as before. Then I remove a from a b c and remove b from b c e, which are equal parts, and the remainders stay equal, that is c e n m is worth c e o. Then I remove e from the one quantity and from the other, and the remainder stays equal, that is c n m. I remove a b, that is by removing b which is double, and there remains a void in b, and a remains single against e which is double. I will remove e single, which is part of c e, and put it back into the void b, and there will remain a b single, and e remains single. But here remains b c o, which has less by e to finish the semicircle against the whole eighth a b c o; whence I will remove from this a b c n e m the part e, and there will remain a b c n m equal to b c o; and in this working c remains double. I will remove it from the one surface and the other; there will remain a n m, equal to b o.

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