H
E
E
L
E
M
E
N
T
S
let HE be greater than C.
Now
HE is equal to GB;
therefore
GB is also greater than C.
Let
KLMN be constructed at once equal to the excess by which GB is greater than C and similar and similarly situated to D. [VI.25]
But
D is similar to GB;
therefore
KM is also similar to GB. [VI.21]
