Geometry Essentials of Geometry

A point. It has no dimesnsion and is just a dot.

A one dimesioned figure that goes on forever. There is only one line no matter how many points are shown on the line. A line is named by the points on it.

A plane is a two dimesioned figure that extends without end in both directions. Planes can be name by three points that are not on the smae line.

Points that are on the same line

Points that are on the same plane.

A line that contains enpoint and does not go on forever.

A ray is a line with one endpoint, and one end goes on forever, like the suns rays.

Rays that are on the same line and share and endpoint. For example, if C is between point A and B on a line, ray CA is the opposite ray of CB

The points that something shares. This can be a line, point, plane, multiple points, etc.

Yes

Okay

AB+BC=AC

It is adding two segments together to become a larger segment, like AB+BC=AC if B is between A and C on the same line.

Equal to. It does not deal with measurements.

A point on a segment that divides the line segment into two congruent segments.

Anything that intersects a line segment at the midpoint, wheter it be a ray, line, ect. It bisects the segment

• The mid point formula is (average the x's, average the y's).
• There are other formulas. but they cannot be written, so if you prefer a different version, look back in your notes!

Find the distance or length between segments

• You can say:
• d²=(subtract the x's)²+(subtract the y's)²
• d= the square root of (x-x)²+(y-y)²
• Write it out!
• Count the boxes on a coordinate question if you can!

Two rays that sare an endpoint.

The point where the two rays intersect.

• 0^o<m<90^o is an acute angle
• m=90^o is a right angle
• 90^o<m<180^o is an obtuse angle
• m=180^o is a straight angle
• 180^o <m<360^o is a reflexive angle

Adding two touching angles that share a ray. m<RSP+m<PST=m<RST if SP is in between rays SR and ST.

A ray that divides an andle into two angles that are congruent.

Two angles that add to 90 degrees, whether they are adjacent/touching or not.

Two angles that add to 180 degrees whether they are adjacent/touching or not.

A pair of supplementary angles that form a straight line. They must be adjacent/next to each other.

They are always congruent. Vertical angles are opposite angles of two intersecting lines.

A closed figure. It is formed by three or more line segments. Each side intersects exactly two sides, so that no sides share a common endpoint and become colinear.

The endpoint of a side. The vertices determine what the name of the polygon is, since they are named in order around the shape.

A convex polygon has sides that stick out, and a concave polygon has sides that go in.

• They're sides are congruent.
• They're angles are congruent.
• It is a convex polygon

a²+b²=c²

• When you are given the lengths and are asked what king of triangle it is, think __.
• If it is =, it is a right trianlge.
• If it is >, then it is an acute trianlge.
• If it is <, then it is an obtuse trianlge