∴△ACB∽△ADC

Exchange advertisement

- = -

AB AC

Get AB*AD=AC*AC

German AC BC AC

∴∠AED=∠ACB

∠BAC=∠DAE (male * * * angle)

∴△DAB∽△DAC

Let AD be X.

De: de AD

- = -

AB BC

That's 70 times

- = -

80 X+55

x=385

x+55=440

∴AB=440