the middle point; the point within a circle equidistant from all points on the circumference or surface

Word Root/Origin:

from Greek kéntron, meaning "needle" or "spur"

Formula(s):

N/A

Image:

the linear distance around the edge of a closed curve or circular object

Word Root/Origin:

from Latin circumferentia, meaning "carrying around"

Formula(s):

C = 2πr

C = πd

Image:

the distance from the center to the edge of a circle

Word Root/Origin:

from Latin radius, meaning "staff, stake, rod"

Formula(s):

r = d/2

r = C/(2π)

Image:

a straight line going through the center of a circle, connecting 2 points on the circumference

Word Root/Origin:

from Greek diametros, dia- "across, through" + metron "measure"

Formula(s):

d = 2r

d = C/π

Image:

a line that just touches a curve at 1 point, without cutting across it

Word Root/Origin:

from Latin tangēns, meaning "to touch"

Formula(s):

N/A

Image:

an unbroken curved line on the circumference of a circle

Word Root/Origin:

from Latin archus, meaning "bow, arch, curve"

Formula(s):

N/A

Image:

a line segment whose endpoints both lie on the circle

Word Root/Origin:

from Latin chorda, meaning "bowstring"

Formula(s):

N/A

Image:

a line passing through 2 points of a curve

Word Root/Origin:

from Latin secāre, meaning "to cut"

Formula(s):

N/A

Image:

the area of a circle made my a line with its connecting arc

Word Root/Origin:

from Latin segmentum, equivalent to sec (āre) "to cut" + -mentum

Formula(s):

Part 2 of unit

Image:

the area between 2 radii with their connecting arc of a circle

Word Root/Origin:

from Latin sector, meaning "cutter"

Formula(s):

Part 2 of unit

Image: