obrazce

Obrazce, in mathematics often called geometric figures, are the basic objects used to describe form, size, and position in space. In Euclidean geometry they are studied as sets of points that satisfy particular rules. Obrazce can be divided into plane (rovinné) and spatial (prostorové) figures. A plane obrazec lies entirely in a two-dimensional plane, while a spatial obrazec has extent in three dimensions.

Plane obrazce include polygons (with straight sides) and smooth curves such as circles, ellipses, and parabolas. Polygons are classified by the number of sides and by properties: convex vs nonconvex, regular vs irregular. A circle is a special case with constant distance from its center. Plane figures are often analyzed by their perimeter and area, and they can be described using coordinates or equations in the plane.

Spatial obrazce include polyhedra (with flat faces: cube, tetrahedron, dodecahedron) and solids with curved surfaces such as spheres, cylinders, cones, and tori. They are described by faces, edges, and vertices, or by algebraic equations in coordinate space. Key measurements for spatial figures include volume and surface area, as well as properties such as symmetry and tessellation.

Representations use coordinates or equations: for example, a circle can be described by (x−a)^2+(y−b)^2=r^2, and a line or polygon by boundary equations or parametric forms. Obrazce have wide applications in education, design, computer graphics, architecture, and CAD, making them central to both theory and practice in geometry.