Construction" in Geometry means to draw shapes, angles or lines accurately. These constructions use the only compass, straightedge (i.e. ruler) and a pencil. This is the "pure" form of geometric construction: no numbers involved!
Constructions The drawing of various shapes using only a pair of compasses and straightedge or ruler. No measurement of lengths or angles is allowed. Applications of geometry in the real world include a computer-aided design for construction blueprints, the design of assembly systems in manufacturing, nanotechnology, computer graphics, visual graphs, video game programming and virtual reality creation.
A tangent to a circle is a line intersecting the circle at exactly one point, the point of tangency or tangency point. A significant result is that the radius from the centre of the circle to the point of tangency is perpendicular to the tangent line.