# GEOMETRY GLOSSARY

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Title Description
SAA Congruence Side-Angle-Angle Congruence establishes two congruent triangles.
SAS Congruence Side-Angle-Side Congruence establishes Congruence between two triangles.
SAS Similarity Side-Angle-Side Similarity employs a fixed ratio between pairs of sides of triangles.
Scalene A triangle is considered Scalene if no two sides have the same length.
Secant The term applies to either a line containing the chord of a circle (or some other line segment between points on a function), or one of the six basic functions in trigonometry, the cofunction of the cosecant and the reciprocal of the cosine.
Second, Degree While "second degree" applies to a polynomial, a single Second with respect to Degree measure is one-sixtieth of one minute, or one sixtieth of one sixtieth of one degree, or 1/1,296,000 of a revolution.
Second, Time One sixtieth of a minute, or 1/3600 of an hour, is one Second of Time.
Sector A piece of a circle bounded by a central angle.
Segment, Circle A portion of a circle bounded by a chord and the circle itself.
Segment, Line A Line Segment is a set of collinear points bounded on both ends with, literally, endpoints.
Semicircle Half a circle; the portion of a circle on one side of a diameter.
Set Any collection of objects or values is considered a Set, whose cardinal number is the number of objects in the Set.
Set Union The Union of two (or more) Sets is the Set that contains both (or all) Sets.
Logically, the Union of two Sets A and B is the Set of elements contained in either Set A or B, literally "A or B."
Similar Geometrically, figures of like shape and proportions are said to be Similar.
Similarity Literally the quality of being Similar, which is to have the same shape and proportions, but not necessarily of the same size.
Simple Closed Curve A planar figure that neither crosses itself or contains a gap is a Simple Closed Curve; note that a curve can be "straight" according to the mathematicians.
Simple Harmonic Motion Periodic Motion with constant length of cycle time (a fixed period) is termed Simple Harmonic Motion.
Sine One of the six basic trig functions, in a right triangle the Sine of an angle is the ratio of the length of the opposite side to the length of the hypotenuse.
Sinusoid A sine wave is called a Sinusoid; a cosine graph is also a Sinusoid.
Skew Lines neither intersecting nor parallel (non-coplanar lines) are termed Skew lines.
Slope A number associated with a line graphed in a plane, Slope is the ratio of rise over run, an indication of the steepness of the line.
We may write a line as y = mx + b and use the value of m for Slope.
Slope-Intercept Equation of a Line The familiar y = mx + b, where m represents Slope and b is the y-Intercept.
SOHCAHTOA A mnemonic device for remembering: sine-opposite-hypotenuse; cosine-adjacent-hypotenuse; tangent-opposite-adjacent.
Also stands for "some old hippie caught another hippie tripping on acid."
Solid A three-dimensional geometric figure or body that includes the interior region.
Solution Too often in math class, "the answer." More directly, a Solution is a value (or set of values) that makes a mathematical statement true.
Speed A (typically fixed) ratio of length or distance to a unit of time; Speed is a scalar value, as in miles per hour (mph) or feet per second (fps).
Sphere A three-dimensional figure comprised of points equidistant from a center point; a Sphere has a fixed radius.
Spherical Geometry Unlike plane Geometry, Spherical Geometry is not based on the parallel postulate.
Many of our accepted geometric theorems, principles, and tenets (from plane Geometry) simply do not hold in Spherical Geometry.
Spheroid An oblate sphere.
Sometimes, an ellipsoid.
Spiral Sometimes Spiral is used to describe a helix.
A genuine Spiral is a plane figure of changing radius from a (usually fixed) origin.
Square One noun: the regular quadrilateral, equilateral and equiangular.
Another noun: the result of multiplying a number times itself.
Or, the verb: the operation of multiplying a number times itself, equivalently raising it to power two.
Square Root Given a real value, the number that times itself (squared) produces the given value is its Square Root
SSA Ambiguity Side-Side-Angle congruence is not enough to establish congruence between two triangles; it is the Ambiguous case.
SSS Congruence Two triangles whose corresponding sides are congruent are themselves congruent.
SSS Similarity When corresponding sides of two triangles are in a fixed ratio the triangles are similar.
Standard Position An angle in Standard Position has been rotated counterclockwise (for positive rotation) from an initial ray on the positive x-axis.
Straight Angle An angle of 180 degrees or pi radians.
Supplementary Supplementary angles sum to 180 degrees, or pi radians.
Symmetry Having a like but reversed profile or image (a mirror image) about a line is having the quality of Symmetry about the axis (of Symmetry).
System of Equations Most generally simultaneous Equations, or a set of Equations with identical variables.

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