Question

In the figure, BD¯¯¯¯¯ bisects ∠ABC .

Answer 1

The bisector BD is perpendicular to the line segment AC then the angle formed in between is 90°. We can solve for DC using SOH CAH TOA theorem or Pythagorean theorem.
Since ∠BDA is 90°, we can examine that AD is equal to 2units. Proving this, we have BD^2=BD^2+AD^2.
3^2=DB^2+2^2
DB=5units
Therefore, DC=AC-AD and the answer is 2 units.