GEOMETRY GLOSSARY
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Title  Description  

SAA Congruence  SideAngleAngle Congruence establishes two congruent triangles. 

SAS Congruence  SideAngleSide Congruence establishes Congruence between two triangles. 

SAS Similarity  SideAngleSide 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 onesixtieth 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 (noncoplanar 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. 

SlopeIntercept Equation of a Line  The familiar y = mx + b, where m represents Slope and b is the yIntercept. 

SOHCAHTOA  A mnemonic device for remembering: sineoppositehypotenuse; cosineadjacenthypotenuse; tangentoppositeadjacent. Also stands for "some old hippie caught another hippie tripping on acid." 

Solid  A threedimensional 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 threedimensional 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  SideSideAngle 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 xaxis. 

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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