Can you name the Definitions Related to Circles?

Definition	Term
A curved line that is part of the circumference of a circle
A line segment within a circle that touches 2 points on the circle
The distance around the circle
The longest distance from one end of a circle to the other
The center of the circle
3.141592...
The distance from center of circle to any point on it
A line perpendicular to the radius that touches ONLY one point on the circle

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Circle Geometry Quiz

Rating:	Report a mistake
Published: February 12th, 2008
Category: Miscellaneous
Plays: 149,470

Tags: Definition Quizzes, related, circle, geometry, term

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	austin massachusetts:	Oct 31st, 2008 at 12:10 GMT	27 points
	A circle isn't always centered at the origin...

	Bodhisvaha:	Nov 16th, 2008 at 01:33 GMT	41 points
	yeah..I think I remember "origin" referring specifically to (0,0) a Cartesian plane. wouldn't "focus" be more appropriate?

	Michael:	Nov 29th, 2008 at 22:38 GMT	13 points
	i agree with Bodhisvaha, focus was (i believe rightly so) my first instinct

	AeroE:	Dec 2nd, 2008 at 04:21 GMT	-2 points
	The origin usually refers to (0,0) of a coordinate system, but often in solving physics or engineering problems involving circles the origin is placed at the center of the circle so the terms focus and origin are often used interchangably.

	eln77:	Dec 5th, 2008 at 03:06 GMT	14 points
	shouldn't focus be an acceptable response for that one then? I tried it, and it didn't take it.

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	adal:	Feb 12th, 2009 at 11:39 GMT	6 points
	got 6/8 - never heard of origin of a circle, and forgot chord. How about adding segment and sector to make it an even 10?

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	archicello:	Feb 24th, 2009 at 16:16 GMT	10 points
	teganx7: im just kinda thinkin it out... but if a line is infinite [are they?] then there is only one possible line perpendicular to a radius that only hits the circle at one point, the tangent. or im wrong :D

	TheDixieFlatline:	Feb 28th, 2009 at 04:01 GMT	6 points
	I agree with the comments about the center - focus should be allowed as well. I even tried 'middle' (in some desperation) before I thought of origin. Archicello is right about the tangent. The only possible way for a line to only touch the circumference at one point is for the rest of the line to lie outside the circle. Unless a length is specified, or end-points, all lines are considered to be infinite.

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	stupidgreen:	Mar 15th, 2009 at 17:10 GMT	-1 points
	Radii are line segments, so the point on the circle which is opposite the intersection of the tangent and a radius is not perpendicular, since they do not intersect.

	adal:	Mar 18th, 2009 at 13:47 GMT	2 points
	@stupidgreen: True, True. I was thinking diameter. Sorry.

	LyzzixLethal:	Apr 10th, 2009 at 20:38 GMT	-3 points
	I though the center of the circle was the vertex. And...secant? Isn't that a segment that touches twice?

	ESkog:	Apr 27th, 2009 at 01:19 GMT	23 points
	I teach math, and the only universally correct term for the center of a circle is "center". "Focus" tends to refer to ellipses or hyperbolas, and the "origin" is specifically the point (0,0) in the Cartesian plane as the above commenters mention.

	zifyoip:	May 22nd, 2009 at 20:19 GMT	10 points
	I have a master's degree in math. I agree with Eric's comment above; for example, the center of the circle (x-1)^2+(y-1)^2=4 is not the origin, it's the point (1,1). "Focus" would be technically correct, though it's not commonly used with reference to circles. Also, to be picky, the fact that a tangent is perpendicular to a radius is not part of the definition of tangent—it's a theorem that requires proof.

	GeoExpert:	May 26th, 2009 at 16:45 GMT	1 point
	Isn't there a more scientific term other than center, but not origin?

	Beks:	May 26th, 2009 at 19:47 GMT	1 point
	I couldn't spell circumference to save my life, but I knew that was the answer

	LaughingTulkas:	May 28th, 2009 at 15:50 GMT	4 points
	should be focus and not origin. A circle is a special case of an ellipse where both foci and located at the same point. Origin is just completely wrong.

	JimKatz:	Jun 13th, 2009 at 06:08 GMT	17 points
	If you got all but "origin," consider it a perfect score.

	PackRat:	Jun 14th, 2009 at 22:01 GMT	6 points
	Nobody calls the center of a circle the origin

	btroup1:	Jun 18th, 2009 at 14:41 GMT	0 points
	Got'em all! One nit to pick: you introduce a later answer in the first question.

	BonesLover:	Jun 21st, 2009 at 13:23 GMT	2 points
	I feel as thought there is WAY to much time

	GuyNemeth:	Jul 31st, 2009 at 19:44 GMT	3 points
	@archicello: I think there's actually an infinite number of tangent lines on a circle. As long as you can take the derivative of the circle and have the result in terms of X and Y (Cartesian Axis), then you can plug in any point on the circle and have the equation of a tangent line to that circle. And since a circle is technically made up of infinite points, therefore you have infinite tangent lines.

	edzoid:	Sep 11th, 2009 at 01:50 GMT	6 points
	'center' is the center of a circle - take it from a grometry teacher.

	BamaMuaddib:	Sep 23rd, 2009 at 06:26 GMT	2 points
	Perhaps the entire center clue could be changed to read, "Midpoint of the diameter." This would reveal diameter as another answer (circumference and radius already are) but at least everyone would get center correct.

	Dr_Corndog:	Jan 21st, 2010 at 16:15 GMT	4 points
	I'm pretty sure the center of a circle is not called the origin.

	jaypunkrawk:	Jan 21st, 2010 at 20:05 GMT	-2 points
	Schooled that one!

	daHOOK:	Jan 29th, 2010 at 00:01 GMT	4 points
	Center is the term for the point in the middle. Both foci of a circle are at the center (centre, if you prefer). Missing from this quiz are segment, secant, and sector.

	rentlix:	Feb 9th, 2010 at 03:46 GMT	3 points
	A circle's center can be at (1,2), which isn't the origin.

	dixon:	Feb 13th, 2010 at 22:15 GMT	0 points
	"secant line" is more accurate than "chord"

	1derflguy:	Mar 1st, 2010 at 18:20 GMT	-4 points
	here is at least one reference that defines the center of the circle as the origin. http://math2.org/math/geometry/circles.htm As unintuitive as it may seem, relative to the circle, that is the origin. Math majors need to put aside the fact that 0,0 is the origin relative to cartesian coordinates. The origin of a circle can in fact have any coordinate pair, based on any system (lat & long, state plane, cartesian, etc.)

	JimAkin:	Apr 5th, 2010 at 14:21 GMT	4 points
	@GuyNemeth is correct. Each radius has a unique perpendicular tangent, but the number of radii is infinite, and therefor so is the number of tangents.

	Endasil:	Apr 8th, 2010 at 04:56 GMT	4 points
	Agree with all others who discount "origin". "Focus" should be acceptable, but really "center" or "centre" is the most correct answer. Maybe reword the question so the answer isn't in the definition?

	tlchi:	May 27th, 2010 at 22:46 GMT	4 points
	Agree with the majority of comments above -- "origin" is wrong; "focus" is acceptable. Maybe change the clue to "point on the plane of the circle that is the same distance from all points of the circle"?

	marsviking:	May 31st, 2010 at 02:10 GMT	2 points
	a secant cuts the circle at two points

	daHOOK:	Oct 14th, 2010 at 17:07 GMT	1 point
	I was hoping sector and segment might be on here, but alas.

	mmomjian:	Dec 10th, 2010 at 04:59 GMT	2 points
	I too put in focus... never heard of origin, the correct answer is "center"... also, where is secant?