Algebra 1 · Inequalities
Closed Circle
Algebra 1 · Inequalities
Definition
A closed circle is a filled-in dot on a number line showing the boundary value is part of the solution.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- x ≥ 4 uses a closed circle at 4.
- x ≤ −1 uses a closed circle at −1.
Key rule
Use a closed circle for ≤ and ≥.
Memory hook
Closed circle = included; the line touches it.