Circle Vocabulary Puzzles

Our Circle Vocabulary Puzzles are a great way to hone students’ math vocabulary skills. Our new puzzles do NOT require any Java applets. We have crosswords puzzles with three levels of difficulty, and our newly-added circle word search. All resources are interactive, engaging, and include a timer. Solutions are also provided. Choose a puzzle below to get started. Be sure to try our related activities, too!

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Featured Circle Geometry Vocabulary Words

Arc – In circle geometry, an arc is a portion of the circumference of a circle. It is defined by two points on the circle called endpoints and the curve connecting them. Arcs are measured by their central angle or their arc length.

Center – The center of a circle is the point that is equidistant from all points on the circumference of the circle. It is often denoted by the letter “O” and serves as the reference point for various circle geometry concepts, such as radius, diameter, and circumference.

Central Angle – A central angle is an angle whose vertex is at the center of a circle, and its sides are two radii of the circle. The measure of a central angle is equal to the measure of the arc it intercepts on the circle.

Chord – A chord of a circle is a line segment whose endpoints lie on the circumference of the circle. It is the longest segment that can be drawn within the circle, and its length can be determined using the Pythagorean theorem.

Circumference – The circumference of a circle is the distance around its outer boundary or perimeter. It is calculated using the formula C = 2πr, where r is the radius of the circle and π is the mathematical constant approximately equal to 3.14159.

Concentric Circles – Concentric circles are circles that share the same center point but have different radii. They are essentially circles nested within one another, resembling a target pattern.

Diameter – The diameter of a circle is a straight line segment passing through the center of the circle and connecting two points on the circumference. It is twice the length of the radius and is a fundamental measurement in circle geometry.

Inscribed Angle – An inscribed angle is an angle formed by two chords of a circle with the vertex on the circle. Its measure is half the measure of the intercepted arc.

Inscribed Circle – An inscribed circle, also known as an incircle, is a circle that is tangent to each side of a polygon from the inside. In a triangle, the inscribed circle is the largest circle that can fit inside the triangle and touches all three sides.

Intercepted Arc – An intercepted arc is the portion of the circumference of a circle that lies between two points on the circle, typically defined by an angle with its vertex at the center of the circle.

Major Arc – A major arc is an arc of a circle that measures more than 180 degrees. It spans more than half of the circle’s circumference.

Minor Arc – A minor arc is an arc of a circle that measures less than 180 degrees. It spans less than half of the circle’s circumference.

Point of Tangency – The point of tangency is the point where a tangent line intersects the circumference of a circle. At this point, the tangent line is perpendicular to the radius of the circle.

Radius – The radius of a circle is a line segment that connects the center of the circle to any point on the circumference. It is half the length of the diameter and is used extensively in circle geometry calculations.

Secant – A secant of a circle is a line that intersects the circle at two distinct points. It can be extended infinitely in both directions.

Sector – A sector of a circle is a region bounded by two radii of the circle and the arc intercepted between them. The area of a sector can be calculated using the formula A = 1/2 r²θ, where r is the radius of the circle and θ is the central angle in radians.

Segment – In circle geometry, a segment refers to a region bounded by a chord and the arc intercepted by the chord. There are two types of segments – major segments and minor segments.

Tangent – A tangent to a circle is a line that intersects the circle at exactly one point, known as the point of tangency. At the point of tangency, the tangent line is perpendicular to the radius of the circle.

Tangent Circles – Tangent circles are circles that intersect at exactly one point, where their circumferences touch externally. They do not intersect or overlap in any other way.

Tangent Line – A tangent line is a straight line that touches a circle at exactly one point, known as the point of tangency. It is perpendicular to the radius of the circle at the point of tangency.

Tangent Segment – A tangent segment is a line segment that is tangent to a circle from an external point. It is the shortest distance from the external point to the circle.