Plane geometry is a two dimensional figure, also called planar geometry, with edges. The edges are line segments or edges and curve segments or arcs, all lying on a flat plane.
Nomenclature & Symbols
Plane Geometry Glossary
- Arc Length of a Circle -
- Catenart Curve -
- Chord of a Circle -
- Circumference of a Circle -
- Diameter of a Circle -
- Foci of an Ellipse -
- Radius of a Circle -
- Semi-major and Semi-minor Axis of an Ellipse -
Plane Geometry Types
- Circle - All points are at a fixed equal distance from a center point.
- 3 Overlapping Circle - Equal length arcs connecting at the vertices of three overlapping circles.
- 3 Connecting Circle - Three equal length arcs connecting at the vertices bound by circles.
- 4 Connecting Circle - Four equal length arcs connecting at the vertices bound by circles.
- Annulus of a Circle - The area between two concentric circles.
- Circle Corner - A right triangle having acute vertices on a circle with the hypotenuse outside the circle.
- Sector of a Circle - A part of the interior of a circle having two radius boundries and an arc.
- Segment of a Circle - An interior part of a circle bound by a chord and an arc.
- Half Circle - Half of the interior of a circle having a straight chord and an arc.
- Hollow Circle - Two circles each having all points on each circle at a fixed equal distance from a center point.
- Quarter Circle - A part of the interior of a circle having two radius boundries at a 90° angle and an arc.
- Thin Wall Circle - Two circles each having all points on each circle at a fixed equal distance from a center point.
- Ellipse - A two-dimensional figure with a conic section or a stretched circle.
- Polygon - A closed plane figure for which all edges are line segments and not necessarly congruent.
- Concave Polygon - A polygon where one or more angles are greater than 180° and some vertices point inward.
- Convex Polygon - A a polygon where all interior angles are less than 180° and all vertices point outward.
- Irregular Polygon - A polygon where all edge and angles are not the same. It can be concave or convex.
- Regular Polygon - A polygon where all edges are congruent and all angles are congruent.
- Self-intersecting Polygon - A polygon where one or more edges cross over another.
- Triangle - A polygon with 3 edges.
- Acute Triangle - Has three angles less than 90°.
- Equilateral Triangle - Has three edges that are the same length and all edges and angles are congruent.
- Isosceles Triangle - Has two edges that are the same length or at least two congruent edges.
- Oblique Triangle - Is tilted at an angle, not horizontal or vertical.
- Obtuse Triangle - Has one of the three angles more than 90°.
- Right Isosceles Triangle - Has one edge a right 90° interior angle and the other two angles are 45°.
- Right Triangle - Has one edge a right 90° interior angle.
- Scalene Triangle - All three edges are different lengths and all three angles are different angles.
- Quadrilateral - A polygon with 4 edge.
- Acute Trapezoid - A trapezoid has two adjacent acute angles on its longer base edge.
- Isosceles Trapezoid - A trapezoid with only one pair of parallel edges and having base angles that are the same.
- Kite - A quadrilateral with two pairs of adjacent edges that are congruent.
- Obtuse Trapezoid - A trapezoid with one acute and one obtuce angle on each base.
- Parallelogram - A quadrilateral with two pairs of parallel opposite edges.
- Rectangle - A quadrilateral with two pair of parallel edges.
- Rhombus - A parallelogram with four congruent edges.
- Right Trapezoid - A trapezoid with only one pair of parallel edges and two adjacent right angles.
- Rounded Corner Rectangle - A quadrilateral with two pair of parallel edges and rounded corners.
- Self-intersecting Rectangle - One edge crosses over another.
- Square - A quadrilateral with four equal edge lengths and 90° interior angles.
- Trapezoid - A quadrilateral that has a pair of parallel opposite edges.
- Tri-equilateral Trapezoid - A trapezoid with only one pair of parallel edges and having base angles that are the same with three congruent edges.
- Pentagon - A polygon with 5 edges.
- Regular Pentagon - A polygon with 5 congruent edges.
- Hexagon - A polygon with 6 edges.
- Regular Hexagon - A polygon with 6 congruent edges.
- Heptagon - A polygon with 7 edges.
- Regular Heptagon - A polygon with 7 congruent edges.
- Octagon - A polygon with 8 edges.
- Nonagon - A polygon with 9 edges.
- Decagon - A polygon with 10 edges.
- Hendecagon - A polygon with 11 edges.
- Dodecagon - A polygon with 12 edges.
- Triskaidecagon - A polygon with 13 edges.
- Tetrakaidecagon - A polygon with 14 edges.
- Pentadecagon - A polygon with 15 edges.
- Hexakaidecagon - A polygon with 16 edges.
- Heptadecagon - A polygon with 17 edges.
- Octakaidecagon - A polygon with 18 edges.
- Enneadecagon - A polygon with 19 edges.
- Icosagon - A polygon with 20 edges.
- Triacontagon - A polygon with 30 edges.
- Tetracontagon - A polygon with 40 edges.
- Pentacontagon - A polygon with 50 edges.
- Hexacontagon - A polygon with 60 edges.
- Heptacontagon - A polygon with 70 edges.
- Octacontagon - A polygon with 80 edges.
- Enneacontagon - A polygon with 90 edges.
- Hectogon - A polygon with 100 edges.
- Chiliagon - A polygon with 1,000 edges.
- Myriagon - A polygon with 10,000 edges.
- Triangle - A polygon with 3 edges.
- Circle Sector
- Circle Segment
- Half Circle
- Hollow Circle
- Hollow Rectangle
- Quarter Circle
- Rectangular Angle
- Regular Polygon
- Rotating Rectangle
- Square Angle
- Square Channel
- Square Diamond
- Square I Beam
- Square T Beam
- Tapered Channel
- Tapered I Beam
- Tapered T Beam
- Thin Wall Circle
- Thin Wall Rectangle
- Unequal I Beam