diameter

(noun)

Two times the radius of a circle.

Related Terms

Examples of diameter in the following topics:

  • Circles as Conic Sections

    • The ratio of a circle's circumference to its diameter is π (pi), an irrational constant approximately equal to 3.141592654.
    • The length of the circumference, C, is related to the radius, r, and diameter, d, by:
    • Diameter: the longest chord, a line segment whose endpoints lie on the circle and which passes through the center; or the length of such a segment, which is the largest distance between any two points on the circle.
    • Radius: a line segment joining the center of the circle to any point on the circle itself; or the length of such a segment, which is half a diameter.

  • Introduction to Circles

    • The diameter is any straight line that passes through the center of the circle.
    • It is the ratio of any circle's circumference to its own diameter.

  • Ellipses

    • The distance between antipodal points on the ellipse, or pairs of points whose midpoint is at the center of the ellipse, is maximum along the major axis or transverse diameter, and a minimum along the perpendicular minor axis or conjugate diameter.

  • Introduction to Variables

    • For example, the relationship between the circumference, $C$, and diameter, $d$, of a circle is described by $\displaystyle \pi =C/d$ .