geometry vocabulary part one. point a point is an exact location on a graph, shape or in...

Geometry VocabularyGeometry Vocabulary

Part One

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 line.The 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

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/angle.endpoint make a VERTEX/angle.

VERTICES/angles are measured in VERTICES/angles are measured in “degrees.”“degrees.”

The corners of a square are its vertices.

When two lines cross, they form vertices.

CONGRUENTCONGRUENT

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

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

CONGRUENT Vertices/Angles means two CONGRUENT Vertices/Angles means two angles are the same.angles are the same.

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The Hershey & Crunch Bar are a Congruent size

SIMILARSIMILAR

Similar shapes have corresponding sides Similar shapes have corresponding sides that are in proportion to each other.that are in proportion to each other.

Similar shapes have EQUAL Similar shapes have EQUAL corresponding angles.corresponding angles.

10 feet 4 feet

5 feet 2 feet

VERTICAL LINEVERTICAL LINE

A VERTICAL LINE goes up & down.A 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

PLANEPLANE

A PLANEA PLANE (no, not the one that flies!) (no, not the one that flies!) is a flat is a flat surface that goes on forever in all directions.surface that goes on forever in all directions.

Imagine sitting on a row boat in the middle Imagine sitting on a row boat in the middle of the ocean. No matter which way you of the ocean. No matter which way you look…all you see is water…forever.look…all you see is water…forever.

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

POLYGONPOLYGONA POLYGON is a “closed” shape.A POLYGON is a “closed” shape.

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

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

Regular polygons have all equal sides and Regular polygons have all equal sides and angles.angles.

POLYGON

NOT POLYGON

TRIANGLESTRIANGLES

Are polygons.Are polygons.

Have 3 sides.Have 3 sides.

Have 180 degrees.Have 180 degrees.

Can be equilateral, isosceles, right, or Can be equilateral, isosceles, right, or scalene.scalene.

QUADRILATERALSQUADRILATERALS

Are polygons.Are polygons.

Have 4 sides.Have 4 sides.

Have 360 degrees.Have 360 degrees.

Can be a square, rectangle, parallelogram, Can be a square, rectangle, parallelogram, rhombus, or trapezoid.rhombus, or trapezoid.

And it continues…And it continues…

5 sides = pentagon5 sides = pentagon

6 sides = hexagon6 sides = hexagon

7 sides = heptagon7 sides = heptagon

8 sides = octagon8 sides = octagon

9 sides = nonagon9 sides = nonagon

10 sides = decagon10 sides = decagon

11 sides = hendecagon11 sides = hendecagon

12 sides = dodecagon12 sides = dodecagon

INTERSECTIONINTERSECTION

Where 2 objects cross.Where 2 objects cross.

If it forms a right angle, they are If it forms a right angle, they are perpendicular.perpendicular.

Ray A intersects the triangle in 2 points.

A

These rays are perpendicular.

OVERLAPOVERLAP

Where 2 shapes cross as if lying on top of Where 2 shapes cross as if lying on top of one another.one another.

These shapes overlap, instead of lying flat.

PROTRACTORPROTRACTOR

We use a PROTRACTOR to measure We use a PROTRACTOR to measure vertices/angles in degrees.vertices/angles in degrees.

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

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

OBTUSE ANGLES are greater than 90 OBTUSE ANGLES are greater than 90 ° ° but less than 180 °.but less than 180 °.

STRAIGHT ANGLE is exactly 180 STRAIGHT ANGLE is exactly 180 °.°.

NAMING ANGLESNAMING ANGLES

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 label.center 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)

Complementary AnglesComplementary Angles

Add up to 90 degreesAdd up to 90 degrees

200

700

Supplementary AnglesSupplementary Angles

Add up to 180 degreesAdd up to 180 degrees

1500 300

AdjacentAdjacent

Side by side, or touchingSide by side, or touching

A B

F C

E D

Sides AB and BC are adjacent, because they share a common point (B).

CorrespondingCorresponding

Relates to or goes withRelates to or goes with

A B

F C

E D

Side AB corresponds to side GH.

G H

L I

K J

INTERIORINTERIOR

INSIDEINSIDE

Angle LGH is an interior angle.

EXTERIOREXTERIOR

OUTSIDEOUTSIDE

This exterior angle is 270 degrees.

PERIMETERPERIMETER

The sum of the side lengths of any figure.The sum of the side lengths of any figure.

5 long

2 wide 2 wide

5 long

Perimeter = 14

AREAAREA

The amount of surface covered by a The amount of surface covered by a shape.shape.

5 long

2 wide 2 wide

5 long

Area = 10 units 2

The EndThe End

Once you study all the “fancy words”, Once you study all the “fancy words”, Geometry is very easy to understand…so Geometry is very easy to understand…so STUDY!STUDY!