📖 Math Dictionary

Diameter

/dy-AM-ih-ter/

Definition

The diameter is a straight line passing through the center of a circle, connecting two points on the edge. It is the longest chord and equals twice the radius (d = 2r).

💡Example

If a circle has a radius of 7 inches, its diameter is 7 × 2 = 14 inches. A pizza with 12-inch diameter has a 6-inch radius.

🎓Used in Grades

Grades 4-10KS2 to GCSEÅrskurs 4-9

🔗Related Terms

Radius

📚Learn More

circles →area of circle →circumference →

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