# Geometry Terms Starting with C-D

The math dictionary section bellow deals with all geometry terms starting with the letters 'C' and 'D'.  As you can see we have a full geometry dictionary available for you to explore. Simply click on the tabs to find the math definitions you are looking for.

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## Math Dictionary of Geometry words: C-D

 Calculate: Perform mathematical operations. Calculator: A device used to perform mathematical operations. Capacity: The amount a container can hold. Carroll diagram: A sorting diagram named after Lewis Carroll. Cartesian plane: Also called the coordinate plane.  Contains two perpendicular axes - X-Axis and Y-Axis.  Points are plotted taking a position from both the x and y axis.  e.g. (3,10). Chord: A line segment connecting two point on a circles perimeter/circumference. Circle: A plane shape drawn by a line whose points are equidistant from a point. This point is known as the center point of the circle. Circumference: The distance around the circle.  Calculated by: C = 2.Pi.r Clockwise: The direction the hands on an analogue clock move. Closed Curve: Any curve where it joins itself at its starting point. Cointerior angles: The inner angles on the SAME side of a line drawn through parallel lines. Co-linear: When objects are situated on the same line. Co-linear points: Three or more points that lie on the same line. Compass (construction): An instrument used to create circles. Complimentary angle: Two angles whose sum EQUALS 90 degrees. Concave: Curved inwards.  The opposite of convex. Concave quadrilateral: A quadrilateral with at least one reflex angle. Concave Polygon: Any polygon with at least one reflex angle. Concentric Circle: Circles different in size, but share a center point. Cone:  A solid shape composed of an circular or elliptical base, and a curved surface which tapers to a vertex. Congruent figures: A congruent figure has all equal sides and all equal angles. Converging lines: Lines that all head in the direction of the same point. Convex: Curved outwards - the opposite of concave. Convex Quadrilaterals: A quadrilateral where no angles are greater than 180 degrees (reflex). Coordinates: Pairs of letters or numbers indicating a points position on the Cartesian/coordinate plane.  They are always indicated with the x-axis value first, then the y-axis.  e.g. (4,7) Coordinate plane: Same as Cartesian Plane Coplanar: Geometric objects that exist on the same plane. Corner: The points where surfaces/vertices meet. Corresponding angles: Angles that have the same position created by one line intersecting two or more parallel lines. Counter Clockwise: Same as anti clockwise. Cross Section: The face that results when a solid shape is cut. Cube: A solid shape whose form is created by 6 congruent squares.  Also one of the 5 Platonic Solids. Cubic: The term used when describing a unit of volume. Cuboid: A right prism created by six rectangular faces.  If all faces are square it is called a cube. Curve: A line that is NOT straight. Cyclic Quadrilaterals: A quadrilateral where a circle can be circumscribed to contain all four vertices. Cylinder: A solid shape composed of two congruent circles and one curved surface. Deca: Prefix meaning 10. Decagon: A 10 sided polygon. Decahedron: A Polyhedron with 10 faces. Decrease: To make smaller in size. Deduct: To subtract or take away. Degree (angle): The unit which angles are measured by. Diagonal: A line joining two NON-adjacent vertices. Diameter: A line connecting two points of a circle, which also includes the center point of the circle. Diamond: A plane shape with 4 equal sides and NO right angles. Also known as a Rhombus. Distance: The length between two points or objects. Divisible: Can be divided without a remainder. Dodeca: Prefix for 12. Dodecagon: A polygon with 12 straight edges. Dodechedron: A Polyhedron with 12 faces.

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