There are 6 apples and 2 oranges.
So the ratio of apples to oranges would be 6:2.
However this can be simplified, because these number have a common factor, which is 2. So you divide 2 by 2, and 6 by 2, and get 1 and 3. So the ratio of apples to oranges in simplified form is 1:3. Hope this explains it :)
If it bisect, then using the Line Bisector Theorem, it must be equal.
So x+6=4x-21
get like terms on 1 side
x+6=4x-21
-x. +21
27= 3x
x=9
plug the x in
CD= 9+6
CD=15
The answer is the second one. 5.2 repeating.