Question

Point B is between A and C. If AB = 6 cm and BC = 11 cm, what is AC?

Answer 1

AC will equal to 17 since it's a full line segment that contains A & C as endpoints. While b is the midpoint which does not have to be equally dissected. With adding AB & BC together will have the full value of the line segment. 

Answer 2

Since AB and BC are both parts of the same line segment, AB+BC=AC. If you do substitution and some algebra, you get 6+11=17. So the answer is 17 cm. Hope that helped!