Question

if D is the midpoint of line AC, C is the midpoint of line AB, and BD=12, what is the length of line AB

Answer 1

Look at the picture.

x + 2x = 12

3x = 12     divide both sides by 3

x = 4

AB = 12 + x

therefore AB = 12 + 4 = 16

Answer: AB = 16.