plane geometry
Two-dimensional math
Plane geometry is the branch of mathematics dealing with figures that exist in a flat, two-dimensional surface—points, lines, angles, triangles, circles, and polygons.
It contrasts with solid geometry, which treats three-dimensional objects.
Most high school geometry courses focus on plane geometry: We proved the theorem using plane geometry.
- triangleThree-sided plane figure
- congruent trianglesFigures with equal corresponding parts
- isosceles triangleThree-sided figure, two congruent
- polygonMultisided plane figure
- rectangleFour-sided, all right angles
circle · axioms · tessellations · mathematics · parallel lines · quadrilaterals · straightedge · compass · square · angle bisector · symmetry · Pythagorean theorem · similarity · area · area formula · theorem · point · line
- geometryangles, circles, angle, shapes, lines
- mathematicsalgebra, arithmetic, calculus, number, addition
- liberal artshumanities, trivium, philosophy, history, classical education
- perspectivelinear perspective, one-point perspective, three-point perspective, vanishing point, horizon line