Essentials of Geometry:An Introduction to the Basics of

Geometry

Mrs. Sangster

Term to Know

Point• A point has no dimension.•It is represented by a dot.•It is named using a letter.

Example:

point A

Term to Know

Line• A line is one dimensional.

•It extends in both directions without end.•It is named using at least two points.

Example:

B

A line AB or line m or AB m

Term to Know

Plane•A plane is two dimensional.

•It is represented by a flat surface similar to a wall or floor.•It extends in all directions without end.•It is named using at least three points.

Example:

plane ABC or plane P P

A

B

C

Term to Know

Line Segment•A line segment contains endpoints.

•It is named using the endpoints.

Example:

B

A line segment AB or AB

Term to Know

Ray• A ray contains one endpoint.

•It extends without end in one direction.•It is named using the endpoint and one other point.

Example:

B

A ray AB or AB

Check for Understanding

Name the following geometric figure.

G H

A.) ray GHB.) ray HGC.) ray HD.) ray G

Postulate to Know

Segment Addition Postulate

A B C

segment AB + segment BC = segment AC

Postulate to Know

Segment Addition PostulateExample:

A 10 B 6 C

Find the length of segment AC.

segment AB + segment BC = segment AC10 + 6 = segment AC

16 = segment AC

Postulate to Know

Segment Addition PostulateExample:

A x B 14.5 C

22

Find the length of segment AB.

segment AB + segment BC = segment ACx + 14.5 = 22

x = 7.5

Check for Understanding

GH = 29.6. Find the value of x.

G x F 21.8 H

A.) 21.8B.) 8.7

C.) 51.4D.) 7.8

Term to Know

Angle• An angle is made up of two rays that share a common

endpoint.•It is named using a point on each side and the vertex.

•Angles are classified into 4 different types.

Example: B

A angle BAC or <BAC or <A

C

Classifying Angles

Acute Angles•Measure less than 90 degrees.

Obtuse Angles•Measure greater than 90 degrees.

Classifying Angles

Right Angles•Measure exactly 90 degrees.

Straight Angles•Measure exactly 180 degrees.

Works CitedSlide #1No Author. “Holding the Sun”. Photograph. n.d. JPEG.< http://www.maniacworld.com/holding-the-sun.html>

Slide #2Tompsett, Michael. “Dot Map of the World”. Digital Art. 23 December 2010. JPEG.< http://fineartamerica.com/featured/dot-map-of-the-world--colour-on-white-michael-tompsett.html>Yoga. Night Sky Space Stars. Photograph. 8 April 2014. JPEG.< http://actionforspace.com/night-sky-space-stars/>

Slide #3No Author. Railroad Tracks. Photograph. n.d. JPEG.< http://geovisualdic.blogspot.com/2012_09_01_archive.html>Rowse, Darren. Converging Lines. Digital Photograph. n.d. JPEG.< http://digital-photography-school.com/converging-lines/>

Slide #4Tensor. “Never Ending Cornfield”. Photograph. n.d. JPEG.< http://www.panoramio.com/photo/96460393>No Author. Infinity Pool. Photograph. n.d. JPEG< http://cdn.designrulz.com/wp-content/uploads/2011/11/infinity-pools.jpg>

Slide #5No Author. Logs in River. Photgraph. n.d. JPEG.<http://www.math.hope.edu/pow.html>No Author. Office Buildings. Photograph. n.d. JPEG<http://www.momentousins.com/blog/?m=201208>

Works CitedSlide #6No Author. Sunset with Sun Rays. Photograph. n.d. JPEG.< http://www.thewilltochoose.com/?attachment_id=65>Stanford, Wikimedia. Jet in Flight. Photograph. n.d. JPEG.<http://www.wired.com/2010/05/laser-gallery/all/1>

Slide #10No Author. Bird Beak. Photograph. n.d. JPEG.< http://elgee18.files.wordpress.com/2011/06/pelican.jpg>Terrain. Birdhouse. Photograph. n.d. JPEG.< http://ecosalon.com/16-minimalist-birdhouses-to-go-totally-cuckoo-over/>

ContentMcDougal and Littell. Geometry. Houghton Mifflin Harcourt, 2007. Print.