Acute Angle

Acute Triangle

Adjacent Sides

Adjacent Vertices

Angle

Angle Bisector

Angle in a Plane

Angular Sector

Annulus

Boundary

Broken Line

Cavalier Projection

Central Angle

Central Angle of a Regular Polygon

Centre of a Circle

Centre of a Line Segment

Centre of a Regular Polygon

Cevian

Circle

Circle in a Geometric Plane

Circular Sector

Circular Segment

Circumference of a Circle

Circumscribed Circle of a Polygon

Closed Curve

Closed Plane Surface

Concave Polygon

Concave Quadrilateral

Concentric

Congruent Figures

Congruent Line Segments

Congruent Polygons

Congruent Sides

Congruent Triangles

Conical Perspective

Conjugate Axis

Convex

Convex Polygon

Convex Quadrilateral

Corresponding Sides

Curvature

Curved line

Decagon

Degree of an Angle

Deltoid

Diagonal

Diagonal of a Polygon

Diameter

Dilation in a Cartesian Plane

Direct Isometry

Dodecagon

Edge of a Polygonal Chain

Enneagon

Equiangular

Equiangular Polygon

Equilateral

Equilateral Hyperbola

Equilateral Polygon

Equilateral Triangle

Equipollence

Equivalent Figures

Exterior Angle of a Polygon

Face of a Solid

Figures With Line Symmetry

Figures with Point Symmetry

Fixed Line

Flip

Focus

Fractal

Frieze

Geoboard

Geometric Figure

Geometric Space

Geometric Transformation

Glide Reflection Symmetry

Golden Rectangle

Half-Plane

Height

Height of a Parallelogram

Height of a Trapezoid

Height of a Triangle

Hendecagon

Heptadecagon

Heptagon

Heron’s Formula

Hexadecagon

Hexagon

Homography

Homothetic Figures

Homothetic Polygons

Hyperbola in a Cartesian Plane

Hypotenuse

Image of a Figure Under a Geometric Transformation

Incident

Incircle, or Inscribed Circle, of a Polygon

Interior Angle of a Convex Polygon

Intersecting Lines

Isosceles Polygon

Isosceles Right Triangle

Isosceles Trapezoid