
Inch to Millimeter Conversion
Multiply inches by 25.4

Acute Angle
An angle of less than 90°

Arc
Any portion of the circumference of a circle.

Chord
Any straight line whose opposite ends terminate on thecircumference of a circle

Complementary Angles
Two angles whose sum is 90°

Diameter
The distance across a circle passing through its center

Equilateral Triangle
A triangle with three equal sides and threeequal angles

Isosceles Triangle
A triangle with two equal sides and two equalangles

Major axis
The long axis of an ellipse

Minor Axis
The short axis of an ellipse

Radius
The distance from the center point of a circle to theoutside circumference

Obtuse Angle
An angle greater than 90°

Right Triangle (angle)
A triangle with one 90° angle

Supplementary Angles
Two angles whose sum is 180°

Circumscribed
A figure bounding so as to touch in as manyplaces possible

Inscribed
A figure encircled so as to touch in as many placespossible

Perpendicular
At 90° to a given plane or line

Symmetrical
A quality in which all the features on either side ofa point, line or a plane are identical

Fraction
A part of a whole, such as ½ or ¼



Draw to scale
Drawing an object to a set proportion such as ½, ¼or double its actual size

Metric System
A decimal system of weights and measures basedon the meter and the kilogram

Bevel
A slanted surface not at 90° to another surface

Chamfer
A beveled corner at the opening of a hole or the end ofa cylindrical part to eliminate sharp edges

Fillet
An interior corner found on cast, forged or molded parts

Knurl
A diamond shaped or parallel pattern cut into cylindricalsurfaced to improve gripping or bonding between parts

Round
An exterior corner found on cast, forged or molded parts

Parallel Lines
Lines that are equidistant/nonintersecting

Skew Lines
Lines that are nonintersecting, nonparallel in 3Dspace

Quadrilateral
A plane figure bounded by four straight sides

Trapezoid
Two sides parallel

Ellipse
A foreshortened circle having a major and a minor axis

Bisect
To divide into two equal parts


