H
E
E
L
E
M
E
N
T
S
the square on AE is also equal to the square on EC.
But
the squares on AF, FE are equal to the square on AE, for the angle at F is right;
and
the squares on EG, GC are equal to the square on EC, for the angle at G is right; [I.47]
therefore
the squares on AF, FE are equal to the squares on CG, GE.
