Every single object that surrounds us has a certain geometric shape or is formed of certain geometric shapes. As we know very well from school, geometric shapes can be characterized by such features as angles, side length, symmetry, radius, diameter, arc length, and so on. There are 2D (two-dimensional) and 3D (three-dimensional) geometric shapes.
The two-dimensional shapes are the simplest ones, and they include such kinds of very commonly used geometric shapes as triangles (which can be right, acute, obtuse, isosceles, scalene, or equilateral), quadrilaterals (like rectangles, squares, diamonds, parallelograms, lozenges, and others), curved geometric shapes (including circles, ellipses, crescents, etc.), multi-angular convexes, concaves, and others.
The three-dimensional geometric shapes are more complex and they can be characterized with such features as faces, vertices, edges, etc. Those kinds of shapes include cylinders, cones, cubes, cuboids, prisms, spheres, ellipsoids, pyramids, tetrahedrons, octahedrons, and some other more complicated shapes.
The fundamental science of geometry studies properties, size, relative position and other features of geometric shapes. It has to do with lengths, heights, volumes, areas, surfaces, planes, and other features of two- and three-dimensional geometric shapes. Geometry is one of the most important branches of mathematics which has a huge number of practical applications in modern technology, architecture, a variety of design, arts, and so on.