Question

What is the value of x?

Enter your answer, as a decimal, in the box.

x=

Answer 1

3.5

Explanation:

Look at the picture.

If ABC is any triangle and AD bisects (cuts in half) the angle BAC, then

`(AB)/(BD)=(AC)/(DC)`

In our triangle we have the proportion:

`(CB)/(DB)=(CA)/(DA)`

We have

CB = 6

DB = 4.2

CA = 5

DA = x

Substitute:

`(6)/(4.2)=(5)/(x)` cross multiply

`6x=(4.2)(5)`

`6x=21` divide both sides by 6

`x=3.5`