Jesus S. answered 12/31/22
Patient, Knowledgeable, and Experienced Northwestern Math Tutor
Given our three equalities of B/A = E/D = F/C, we can rearrange variables to get something that's easier to work with.
From B/A = F/C, we get BC = FA by cross multiplying.
Note that F = D+E, so by substituting we see that BC = FA = (D+E)A = DA + AE.
So BC = DA + AE and thus rearranging we get AE = BC - DA.
Note that from the equality B/A = E/D, we get that BD = AE.
So now we get BD = BC - DA
Note that C = A+B, so substituting gives us BD = B(A+B) - DA.
Add DA to both sides and we have BD+DA = B(A+B).
We can now factor a "D" from the left side and get D(B+A) = B(A+B).
Thus, D(B+A) = B(A+B), and as B+A = A+B, we can divide both sides by A+B and get B=D, as desired.

Dayv O.
nice work, I think Plato has just two algebra problems in his work, the other is in Meno dialogue regarding how to find square side length for square with area 8 units squared (twice 4 units squared).01/01/23