Geometry Final Terms

Covering Final Terms Units for semester 1 (Units 1-4)

Acute Angle

An angle with less than 90 degrees

Right angle

An angle with 90 degrees

Obtuse Angle

An angle with more than 90 degrees

Adjacent Angles

2 angles that share a common vertex and a common side but do not overlap

Collinear points

Three or more points that lie on the same single straight line.

Coplanner

A set of points, lines, or figures that all lie on the same two-dimensional flat surface, or plane.

Complementary Angles

2 Angles that add up to exactly 90 degrees

Congruent

Angles that have the exact same measure (in degrees or radians), meaning they are identical in size and shape, even if their orientation or position differs.

Linear Pair

A pair of adjacent angles that are supplementary, meaning they add up to 180 degrees.

Plane

A fundamental, flat, two-dimensional surface that extends infinitely in all directions, having length and width but no thickness or edges, like an endless tabletop or wall.

Postulate

A fundamental statement that is accepted as true without proof

Ray

A part of a line that has one endpoint and extends infinitely in one direction.

Opposite Rays

Two Rays that have a common endpoint and extends in opposite directions, forming a straight line.

Supplementary Angles

Two angles that add up to exactly 180 degrees.

Vertex of an Angle

The angle formed at a “corner” (vertex) where two lines, rays, or sides of a shape meet.

Vertical Angles

A pair of opposite angles formed by two intersecting lines.

Transversal

A line intersecting two or more lines.

Corresponding Angles

In the same relative position at each intersection.

Alternate Interior Angles

On opposite sides of the transversal, between the two lines.

Consecutive Interior Angles

On the same side of the transversal, between the two lines.

Perpendicular Lines

Intersect at a 90 degrees angle

Parallel Lines

Never Intersect and are in the same plane.

Skew Lines

Coplanar lines that never intersect.

Interior Angles

Angles between the two lines.

Exterior Angles

Angles outside the two lines.

Same-side Interior (Consecutive) Angles

Interior Angles on the same side of the transversal.

Transformation

A movement of a geometric figure (ex: Translation, rotation, reflection)

Isometry

A transformation preserving size and shape

Auxillary Line

A line added to help with a proof.

Converse

The reverse statement of a conditional statement.

Polygon

A closed shape with straight sides

Quadrilateral

A four-sided polygon

Convex/Concave

Describes if a polygon’s sides extend inward (concave) or not (convex).

Diagonal

A line segment connecting non-adjacent vertices.

Interior Angle Sum

Formula: (n-2) x 180 degrees for an n-sided polygon.

Translation

Sliding a figure

Rotation

Turning around a fixed point (center of rotation).

Reflection

Flipping across a line (line of reflection).

Dilation

Enlarging or reducing a figure by a scale factor from a center.

Symmetry

Line (reflection) and Rotational.

SOH COH TOA

Acronym for Sine (Opposite/Hypotenuse), Cosine (Adjacent/Hypotenuse), Tangent (Opposite/Adjacent).

Hypotenuse

Side opposite the right angle.

Opposite/Adjacent

Sides relative to a specific acute angle

Angle of Elevation/Depression

Angles used in real-world trig problems.