Basic geometry is a branch of mathematics that deals with the properties and relationships of shapes, sizes, and figures. It includes the study of points, lines, angles, surfaces, and solids. Common geometric shapes include triangles, squares, circles, and rectangles, each with specific characteristics and formulas for calculating area and perimeter. In geometry, concepts such as congruence and similarity help us understand how shapes relate to one another. For example, two shapes are congruent if they are the same size and shape, while similar shapes have the same shape but different sizes. Geometry is essential in various fields, including art, architecture, and engineering.