The segment addition postulate states the following for 3 points that are collinear.

If 3 points A, B, and C are collinear and B is between A and C, then
AB + BC = AC
Suppose AC = 48, find the value of x. Then, find AB and BC
AB + BC = AC
( 2x  4 ) +( 3x + 2 ) = 48
2x + 3x  4 + 2 = 48
5x  4 + 2 = 48
Add 4 to both sides of the equation
5x  4 + 4 + 2 = 48 + 4
5x + 2 = 52
Subtract 2 from both sides
5x + 2  2 = 52  2
5x = 50
Divide both sides by 5
5x / 5 = 50 / 5
x = 10
AB = 2x  4
AB = 2 × 10  4
AB = 20  4 = 16
BC = 3x + 2
BC = 3 × 10 + 2
BC = 30 + 2 = 32
Suppose XA = 3x and AY = 4x  6. If A is the midpoint of XY, what is the length of XY?
3x 4x  6
_________________________________
X A Y
If A is the midpoint, XA = AY.
3x = 4x  6
Subtract 3x from both sides
3x  3x = 4x  3x  6
0 = x  6
Add 6 to both sides of the equation
0 + 6 = x  6 + 6
6 = x
XA = AY = 3 × 6 = 16
XY = XA + AY = 16 + 16 = 32
Nov 09, 18 09:40 AM
Learn the three properties of congruence. Examples to illustrate which property.
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
Nov 09, 18 09:40 AM
Learn the three properties of congruence. Examples to illustrate which property.
Our Top Pages
Formula for percentage
Compatible numbers
Basic math test
Basic math formulas
Types of angles
Math problem solver
Algebra word problems
Surface area of a cube
Finding the average
Scale drawings
Everything you need to prepare for an important exam!
K12 tests, GED math test, basic math tests, geometry tests, algebra tests.
Real Life Math Skills
Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.