okay so here's the problem that i found on the net...

"in the picture, AD is angle bisector if AB + AD = CD and AD + AC = BC ,

angle ACB = 20 degree,"

find angle ABC

here's the link to the picture (

http://img694.imageshack.us/img694/6562/pb3.png)

and there are hints onto solving this problem as well... but i still can't doooo it.

"AD is a bisector implies

AB : AC = area(ABD) : area(ADC) = BD : DC

Use this to express BC/AB and hence cos(angle ACB) in

terms of k = AC/AB. Now, what is sin(angle ABC) in terms

of k and sin(angle ACB)?"