Answer:
BC = 3
Explanation:
If you picture A, B, and C on a line, the first part of the line, AB, has a length of 5 and the total line, AC, has a length of 8 . Means that the second part of the line, BC, has a length of 3 because you would add the length of both the first and second part of the line in order to get the total length of the line.
AB + BC = AC
5 + BC = 8
BC = 3