If the angle bisector also bisects the opposite side, then it's also a median *and* an altitude. The triangle is isosceles.
Draw the diagram: you have that altitude forming a pair of mirror-image right triangles. In each, the short side is 1 and the hypotenuse is 2. What does this tell you about the large triangle?
Then the rest you have to think... cuz it wasn't that hard.( If you still don't understand comment it, and then I will explain to you!)
HOPE IT HELP!