Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Symmetries: Axial Symmetry

Description

This lecture covers axial symmetry, where an isometry transforms points across a line. The construction of a point's symmetrical image is explained using circles. The lecture also discusses the properties of symmetrical points and lines.

Official source

Related concepts (13)

Circle

A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. The distance between any point of the circle and the centre is called the radius. Usually, the radius is required to be a positive number. A circle with (a single point) is a degenerate case. This article is about circles in Euclidean geometry, and, in particular, the Euclidean plane, except where otherwise noted. Specifically, a circle is a simple closed curve that divides the plane into two regions: an interior and an exterior.

Construction

Construction is a general term meaning the art and science to form objects, systems, or organizations, and comes from Latin constructio (from com- "together" and struere "to pile up") and Old French construction. To construct is the verb: the act of building, and the noun is construction: how something is built, the nature of its structure. In its most widely used context, construction covers the processes involved in delivering buildings, infrastructure, industrial facilities, and associated activities through to the end of their life.

Tangent lines to circles

In Euclidean plane geometry, a tangent line to a circle is a line that touches the circle at exactly one point, never entering the circle's interior. Tangent lines to circles form the subject of several theorems, and play an important role in many geometrical constructions and proofs. Since the tangent line to a circle at a point P is perpendicular to the radius to that point, theorems involving tangent lines often involve radial lines and orthogonal circles. A tangent line t to a circle C intersects the circle at a single point T.

Construction management

Construction management (CM) is a professional service that uses specialized, project management techniques and software to oversee the planning, design, construction and closeout of a project. The purpose of construction management is to control the quality of a project's scope, time / delivery and cost—sometimes referred to as a project management triangle or "triple constraints." CM is compatible with all project delivery systems, including design-bid-build, design-build, CM At-Risk and Public Private Partnerships.

Apollonian circles

In geometry, Apollonian circles are two families (pencils) of circles such that every circle in the first family intersects every circle in the second family orthogonally, and vice versa. These circles form the basis for bipolar coordinates. They were discovered by Apollonius of Perga, a renowned Greek geometer. The Apollonian circles are defined in two different ways by a line segment denoted CD.

Related lectures (50)

Bisectrix: Symmetry and Angles

Explores the concept of bisectrix in angles and its symmetries.

Regular Polyhedra in Euclidean Geometry

Explores the historical background and properties of regular polyhedra in Euclidean geometry, including the construction of perfect even numbers and the proportionality of arcs and angles.

Symmetry in Geometry

Explores modern symmetry in geometry, covering transformations, isometries, orientations, and practical applications.

Mediatrice: Construction and Justification

Covers the construction and justification of the mediatrice as the axis of symmetry for a segment.