Then, since EH is equal to EL,
BC is also equal to MN. [III. 14]
Again, since AE is equal to EM, and ED to EN,
AD is equal to ME, EN.
But ME, EN are greater than MN, [I. 20] and MN is equal to BC;
therefore AD is greater than BC.
And, since the two sides ME, EN are equal to the two sides FE, EG,
and the angle MEN greater than the angle FEG,
therefore the base MN is greater than the base FG. [I. 24]
But MN was proved equal to BC.
Therefore the diameter AD is greatest
and BC greater than FG.