Points A, B, C, and D, in that order, lie on a line. If AB = 2 cm, AC = 5 cm, and BD = 9 cm, what is CD, in centimeters?	Choose one.
A) 1	B) 2	C) 3	D) 6	E) 5
Putting a value to each point, lets use the following:   A - 0   B - 2 (AB = 2)   C - 5 (AC = 5)   D - 11 (BD = 9)   CD is 11-5= 
<gadget id="calculator">11-5</gadget>
<output>6</output>
6.   Ans 6
<result>D</result>
Points A, B, C, and D, in that order, lie on a line. If AB = 2 cm, AC = 5 cm, and BD = 9 cm, what is CD, in centimeters?