Algebra 1 · Inequalities
Open Circle
Algebra 1 · Inequalities
Definition
An open circle is a hollow dot on a number line showing the boundary value is not part of the solution.
Examples
- x > 4 uses an open circle at 4.
- x < -1 uses an open circle at -1.
Key rule
Use an open circle for < and >.
Memory hook
Open circle = excluded; the value is left out.