what is a diameter?

Question

is the radius all the way thru the circle or is that the diameter?

Answer 1

A diameter is a line segment that passes through the centre of the circle and has its end points on the circumference.

diameter = 2 x radius

Answer 2

In geometry, a diameter (Greek words diairo = divide and metro = measure) of a circle is any straight line segment that passes through the center and whose endpoints are on the circular boundary, or, in more modern usage, the length of such a line segment. When using the word in the more modern sense, one speaks of the diameter rather than a diameter, because all diameters of a circle have the same length. This length is twice the radius. The diameter of a circle is also the longest chord that the circle has.

For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the width is defined to be the smallest such distance. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance.

The diameter of a connected graph is the distance between the two vertices which are furthest from each other. The distance between two vertices a and b is the length of the shortest path connecting them (for the length of a path, see Graph theory).

The three definitions given above are special cases of a more general definition. The diameter of a subset of a metric space is the least upper bound of the distances between pairs of points in the subset. So, if A is the subset, the diameter is

sup { d(x, y) | x, y ∈ A } .

In medical parlance the diameter of a lesion is the longest line segment whose endpoints are within the lesion.

Answer 3

If a Straight line passing through the circle passes through the centre of circle, the distance between the points of intersection of the line with the circle is called Diameter.

Thus it is the longest Chord in a circle & is twice the radius of the circle. A diameter always divided the circle in to two equal parts.

Answer 4

Inside a circle is an infinite amount of diameters. A diameter is a special chord that cuts the circle into a symmetry. A radius is a diameter cut in hal.
The circumference is measured by using pi, multiplied by the diameter (2 radii) the area is pi multiplied by radius squared.

Answer 5

The diameter is the length of a line that passes through the center of a circle, it goes from any side of the circle to the exact opposite through the center

The radius is the length of line that measures the distance from the center of a circle to any side of the circle. (it's half the diameter)

D=2R

D is diameter
R is radius

Diameter = 2 Radius

Answer 6

Diameter is all the way through the circle; the radius is from the middle point to one side of the circle.

Answer 7

Diameter is the chord of a circle passing thru the centre of the circle having end points on the circumference. It is the biggest chord

Answer 8

The diameter is the length of a line that passes through the center of a circle, it goes from any side of the circle to the exact opposite.

The radius is the length of line that measures the distance from the center of a circle to any side of the circle. (it's half the diameter)

D=2R

D is diameter
R is radius

it's not a mathematician's definition, but I hope it helps.

Answer 9

The diameter is all the way through the circle.

Answer 10

di·am·e·ter [dī ámmətər]
(plural di·am·e·ters)
noun
1. line through center of circle: a straight line running from one side of a circle or other rounded geometric figure through the center to the other side, or the length of this line
2. width: the width or thickness of something, especially something circular or cylindrical
in diameter

3. optics magnifying power of lens: the unit of measurement for the magnifying power of a lens

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