Solution: According to the triangle similarity principle, we can get: 1.8/ 1.7 = BC/AB, 3.84/ 1.7 = BC', /AB.

It can be obtained by transformation: BC'-BC =1.7 * ab/3.84-1.7ab/1.8 =12.

Calculate AB =12/[1.7 * (11.8-1/3.84)] =? Please calculate for yourself.

I wish you progress in your study!