A. POINTS IN SPACE
A point is an exact location in space or on a drawing surface. Appoint is actually represented on the drawing by a crisscross at its exact location. The exact point in space is where the two lines of the crisscross intersect. When a point is located on an existing line, a light, short dashed line or cross bar is placed on the line at the location of the exact point. Never represent a point on a drawing by a dot; except for sketching locations.
B. LINE
Lines are straight elements that have no width, but are infinite in length (magnitude), and they can be located by two points which are not on the same spot but fall along the line. Lines may be straight lines or curved lines. A straight line is the shortest distance between two points. It can be drawn in any direction. If a line is indefinite, and the ends are not fixed in length, the actual length is a matter of convenience. If the end points of a line are important, they must be marked by means of small, mechanically drawn crossbars, as described by a pint in space.
C. ANGLE
An angle is formed by the intersection of two lines. There are three major kinds of angles: right angels, acute angles and obtuse angles. The right angle is an angle of 900, an acute angle is an angle less than 900, and an obtuse angle is an angle more than 900. A straight line is 1800. The symbol for an angle is < (singular) and <’s (Plural). To draw an angle, use the drafting machine, a triangle, or a protractor.
D. TRIANGLES
A triangle is a closed plane figure with three straight sides and their interior angles sum up exactly 1800. The various kinds of triangles: a right triangle, an equilateral triangle, an isosceles triangle, and an obtuse angled triangle.
E. QUADRIALTERAL
It is a plane figure bounded by four straight sides. When opposite sides are parallel, the quadrilateral is also considered to be a parallelogram.
F. POLYGON
A polygon is a closed plane figure with three or more straight sides. The most important of these polygons as they relate to drafting are probably the triangle with three sides, square with four sides, the hexagon with six sides, and the octagon with eight sides.
G. CIRCLE
A circle is a closed curve with all points on the circle at the same distance from the center point. The major components of a circle are the diameter, the radius and circumference.
♦ The diameter of the circle is the straight distance from one outside curved surface through the center point to the opposite outside curved surface.
♦ The radius of a circle is the distance from the center point to the outside curved surface. The radius is half the diameter, and is used to set the compass when drawing
a diameter.
♦ A central angle: is an angle formed by two radial lines from the center of the circle.
♦ A sector: is the area of a circle lying between two radial lines and the circumference.
♦ A quadrant: is a sector with a central angle of 900 and usually with one of the radial lines oriented horizontally.
♦ A chord: is any straight line whose opposite ends terminate on the circumference of the circle.
♦ A segment: is the smaller portion of a circle separated by a chord.
♦ Concentric circles are two or more circles with a common
center point.
♦ Eccentric circles are two or more circles with out a common center point.
This post was written by: Author Name
Your description comes here!
Get Free Email Updates to your Inbox!
Post a Comment