Question

If in a ∆ABC, CD is the angle bisector of the angle ACB, then CD is equal to

• A.
• B.
• C.
• D. None of these

Answer 1

Answer: (C)

Answer 2

∆CAB = ∆CAD + ∆CDB

⇒$\frac { 1 } { 2 }$ab sin C =$\frac { 1 } { 2 }$b .CD. sin(C/2) +$\frac { 1 } { 2 }$a .CD sin(C/2)

⇒ CD (a + b) sin(C/2) = ab(2sin(C/2) cos(C/2)) ⇒ CD

=.