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Geometry VocabularyGeometry Vocabulary

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What is Geometry?What is Geometry?

Geometry is the study of shapesGeometry is the study of shapes

They studied Geometry in Ancient They studied Geometry in Ancient Mesopotamia & Ancient EgyptMesopotamia & Ancient Egypt

Geometry is important in the art and Geometry is important in the art and construction fieldsconstruction fields

An exact position or location

POINTPOINT

A POINT is an exact location on a graph, A POINT is an exact location on a graph, shape or in “space”.shape or in “space”.

The Hershey Kiss is a POINT on the lineThe Hershey Kiss is a POINT on the line

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LINELINE

A LINE goes in opposite directions and A LINE goes in opposite directions and never, never, never ends.never, never, never ends.

Imagine if this Twizzler went on forever and ever and ever and ever and ever and ever

RAYRAY

A RAY is part of a line, but it has one A RAY is part of a line, but it has one endpoint and the other end keeps going.endpoint and the other end keeps going.

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Endpoint

Raaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyy

ENDPOINTENDPOINT

An ENDPOINT is a point at the end of a An ENDPOINT is a point at the end of a ray or line segment.ray or line segment.

Endpoint

LINE SEGMENTLINE SEGMENT

A LINE SEGMENT is part of a ray or line.A LINE SEGMENT is part of a ray or line.

It has two endpointsIt has two endpoints

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Line Segment

Line Line

Ray

●Endpoints

RAY: A part of a line, with one endpoint, that continues without end in one direction

LINE: A straight path extending in both directions with no endpoints

LINE SEGMENT: A part of a line that includes two points, called endpoints, and all the points between them

VERTEXVERTEX

A VERTEX is a fancy name for “angle”A VERTEX is a fancy name for “angle”

Two rays or lines that have the same Two rays or lines that have the same endpoint make a VERTEX/angleendpoint make a VERTEX/angle

VERTEX/angles are measured in VERTEX/angles are measured in “degrees”“degrees”

The Corners of a square are its vertex/angles

When two lines cross, they make vertex/angles

CONGRUENTCONGRUENT

CONGRUENT means the “same”CONGRUENT means the “same”

CONGRUENT LINE SEGMENTS means CONGRUENT LINE SEGMENTS means two line segments are the sametwo line segments are the same

CONGRUENT Vertex/Angles means two CONGRUENT Vertex/Angles means two angles are the sameangles are the same

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The Hershey & Crunch Bar are a Congruent size

VERTICAL LINEVERTICAL LINE

A VERTICAL LINE goes up & downA VERTICAL LINE goes up & down

The candy bars are vertical

HORIZONTAL LINEHORIZONTAL LINE

A HORIZONTAL LINE goes “across” (left A HORIZONTAL LINE goes “across” (left and right)and right)

The candy bars are Horizontal

INTERSECTING LINES: Lines that cross

PARALLEL LINES: Lines that never cross and are always the same distance apart

Perpendicular LinesPerpendicular Lines

Two lines that intersect to form four right angles

OPEN & CLOSED FIGURESOPEN & CLOSED FIGURES

A CLOSED FIGURE/SHAPE starts and A CLOSED FIGURE/SHAPE starts and ends at the same point.ends at the same point.

An OPEN FIGURE/SHAPE does NOT An OPEN FIGURE/SHAPE does NOT start and end at the same point.start and end at the same point.

CLOSED OPEN

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Start

End

Start

End

POLYGONPOLYGON

A POLYGON is a “closed” shapeA POLYGON is a “closed” shape

A POLYGON is made up of line segments A POLYGON is made up of line segments that do not cross. that do not cross.

The number of sides gives a POLYGON The number of sides gives a POLYGON its nameits name

POLYGON

NOT POLYGON

The figure formed when two rays share the same endpoint

Right Angle:An angle that forms a square corner

Acute Angle:An angle less than a right angle

Obtuse Angle:An angle greater than a right angle

3 TYPES OF ANGLES3 TYPES OF ANGLES

ACUTE ANGLES are less than 90ACUTE ANGLES are less than 90°°

3 TYPES OF ANGLES3 TYPES OF ANGLES

RIGHT ANGLES measure exactly 90 RIGHT ANGLES measure exactly 90 °°The “square” symbol means 90’

Right Angle

Right Angle

Not! Not!

Not!

Not!

3 TYPES OF ANGLES3 TYPES OF ANGLES

OBTUES ANGLES are greater than 90 OBTUES ANGLES are greater than 90 ° ° but less than 180 °but less than 180 °

ANGLESANGLES

When you “name” an angle. The When you “name” an angle. The vertex/angle “letter/number” goes in the vertex/angle “letter/number” goes in the center of the labelcenter of the label

A

B

C

If I wanted to know the measurement of Angle A…I would ask:” What is the measurement for BAC?” (Notice A is in the center)