Geometry: Points, Lines, Angles, Circles, and Multiview Drawing

Points

xact "location" in space that is defined by coordinates that are located relative to a known origin point.

Lines

a line is a segment defined by two endpoints. The endpoints are defined with coordinates.

Points that lie on the same line

collinear

Noncollinear points

points that do not lie on the same line

Angle

two, noncollinear lines have the same endpoint.

Vertex

A point where two or more straight lines meet.

the vertex should be the middle letter in the series.

The angle formed by the lines above is referred to as angle ABC.

Right Angle

The angle between the sides measures exactly 90 degrees.

When two lines meet to form a right angle

perpendicular

Acute Angle

The angle between the sides measures less than 90 degrees.

Obtuse Angle

The angle between the sides measures greater than 90 degrees but less than 180 degrees.

Complementary Angles

Two angles whose sum is 90 degrees

Supplementary Angles

Two angles whose sum is 180 degrees

Opposite Angles

When two lines cross, they form 4 angles. The opposite angles have the same measure.

Adjacent Angles

Where two lines cross, angles that share a common side and common vertex. The sum of any two adjacent angle equals 180 degrees.

Circles

A circle can be defined by its center point and either a diameter or radius

Tangent

When a line touches a circle at only one point.

Concentricity

When two or more circles share a common center point they are concentric.

Eccentricity

When two or more circles do not share a common center point they are eccentric.

Quadrilateral

a four-sided polygon

Triangles

any polygon with 3 sides and 3 angles

Hexagons

six-sided figures

Cylinders

three-dimensional object that is defined by its the diameter or radius, its length, and the location of its center axis.

Coaxial

When two or more cylinders are aligned along the same center axis they are

here are 6 regular views of an object

front, top, bottom, right, left and rear (or back) view.

Multiview drawing

technique used by drafters and designers to depict a three-dimensional object using a series of related two-dimensional views.

"Glass Box" Technique

drafter imagines the object inside a glass box and the views of the object are projected onto the surrounding glass panes.

Center Lines-

Represent the centers of circles, arcs and other features

Visible Lines-

Represent the object's visible edges and features

Leader Lines-

show notes

Hidden Lines-

invisible features

Dimension Lines-

Used to define the size and location of an object's features.

oblique plane

passes through the body at an angle

center lines

lines that define the center of an arc,circle, or symmetrical parts.