Concepts of technical drawing.

Radius

• The radius of a circle or sphere is the length of a line segment from its center to its perimeter. The name comes from Latin radius, meaning "ray" but also the spoke of a chariot wheel.
• If an object does not have a center, the term may refer to its circumradius, the radius of its circumscribed circle or circumscribed sphere. In either case, the radius may be more than half the diameter, which is usually defined as the maximum distance between any two points of the figure.

Radius.

Diameter.

• A diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere.
• The length of a diameter is also called the diameter. In this sense one speaks of the diameter rather than a diameter (which refers to the line itself), because all diameters of a circle or sphere have the same length, this being twice the radius r.

Diameter.

Length

• Length is the most extended dimension of an object. In the International System of Quantities, length is any quantity with dimension distance. In other contexts "length" is the measured dimension of an object.

Length.

Perimeter.

• It refers to the contour of a surface or a figure and that the measure contou

Perimeter.

Bibliography.

• definicion.de/perimetro/
• https://en.wikipedia.org/wiki/Length
• https://en.wikipedia.org/wiki/Diameter