Segment Addition Postulate Calculator
Solve AB + BC = AC for the missing segment.
Enter your values
ⓘ Live results
Results
- Solved AC
- 12
- AB
- 7
- BC
- 5
- AC
- 12
- Check
- AB + BC = AC ✓
Working
- 17 + 5 = 12
Quick answer
The segment addition postulate says that if B is between A and C, then AB + BC = AC.
AB + BC = AC
How to use the Segment Addition Postulate Calculator
- 1Choose which segment is unknown.
- 2Type the two lengths you know.
- 3Read the missing length and the consistency check.
Worked example
Using the values the calculator loads with:
Inputs
- Solve forAC (whole)
- AB7
- BC5
- AC12
Results
- Solved AC12
- AB7
- BC5
- AC12
- CheckAB + BC = AC ✓
- 7 + 5 = 12
Frequently asked questions
What is the segment addition postulate?
If point B lies on segment AC between A and C, the two shorter pieces add to the whole: AB + BC = AC.
Can AB be longer than AC?
No — the whole segment AC is always the largest, so a negative result means the labels are swapped.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.