Acute Angle

Acute Triangle

Adding Vectors

Adjacent

Adjacent Angles

Adjacent Faces

Adjacent Sides

Adjacent Vertices

Algebraic Measure

Alternate Angles

Alternate Exterior Angles

Alternate Interior Angles

Amplitude of a Periodic Function

Amplitude of a Sinusoidal Function

Angle

Angle Bisector

Angle in a Plane

Angle of Depression

Angle of Elevation

Angle Of Rotation

Angular Sector

Annulus

Apex

Apothem of a Regular Polygon

Arc

Arc Cosecant

Arc Cosine

Arc Cotangent

Arc Sine

Archimedean Solid

Archimedes of Syracuse (c. 287- c. 212 BCE)

Area of a Circle

Area of a Polygon

Asymptote

Auguste Ferdinand Möbius (1790-1868)

Axial Symmetry

Axis of Revolution

Axis of Symmetry

Axonometric Projection

Azimuth

Base Element

Base of a 2-Dimensional Figure

Base of a Geometric Solid

Basis for a Vector Space

Bipoint

Bipyramid

Boundary

Broken Line

Cabinet Perspective

Cabinet Projection

Carl Friedrich Gauss (1777-1855)

Cartesian Coordinate System

Cartesian Coordinates of a Point

Cartesian Graph

Cartesian Plane

Cartesian System

Cavalier Perspective

Cavalier Projection

Central Angle

Central Angle of a Regular Polygon

Central Projection

Centre

Centre of a Circle

Centre of a Hyperbola

Centre of a Line Segment

Centre of a Regular Polygon

Centre of a Sphere

Centre of an Arc of a Circle

Centre of Dilation

Centre of Gravity of a Triangle

Centre of Rotation

Centre of Symmetry of a Geometric Figure

Centroid

Cevian

Change of Scale

Chord

Circle

Circle in a Cartesian Plane

Circle in a Geometric Plane

Circular Function

Circular Sector

Circular Segment

Circumference

Circumference of a Circle

Circumference of a Sphere

Circumscribed Circle of a Polygon

Closed Curve

Closed Plane Surface

Coefficient of Proportionality

Collinear Points

Collinear Vectors

Compass

Complementary Angles

concave

Concave Polygon

Concave Quadrilateral

Concavity

Concentric

Concentric Circles

Concurrent Lines