Question

1) Find the missing side length

A) 6
B) 7
C)8
D) 9

Answer 1

B

Explanation:

AD is an angle bisector and divides the opposite sides into segments that are proportional to the other 2 sides , that is

`(AC)/(AB)` =
`(CD)/(BD)` , substitute values

`(12)/(21)` =
`(4)/(BD)` ( cross- multiply )

12 BD = 84 ( divide both sides by 12 )

BD = 7 → B