how to deduce the third side of a triangle with given info.

[aryan]

• in a triangle ABC, AD is the bisector of angle BAC, meeting BC at D. if AC = 21 cm, BC =12 cm and the length of BD is 2 cm less than DC, then the length of side AB is:

[Sensei]

I would start from drawing it on piece of paper (or 3D application) to visualize it..

[aryan]

Thank you for replying but i got it solved with the bisector something theorem. I thought it would take some time here to get an answer but it seems community here is really helpful. i will surely post my next question with a proper diagram.