Unit 1- The Language Of Geometry Flashcards
A line
- Goes on forever in both directions
- Named with only 2 points on a line or a lower case letter
A point
- Lies on a coordinate
- Named with a capital letter
A plane
-named with 3 points that are not all on the same line or 1 single capital letter with a plane by it
Line postulate
Through any 2 points is exactly 1 line
Plane postulate
Through any 3 points that are not on the same line, there is exactly 1 plane
Segment
A line with a definite starting point and stopping point
Ray
A line that has one definite point but the other goes on forever
Collinear points
Points that lie on the same line
Opposite rays
2 rays that have the same starting point but go on in opposite directions
Congruent segments
Line segments that are the same length
Midpoint
The middle of a line segment
Segment bisector
When 2 lines, line segments or Rays intersect directly in the center of the other
Coplanar points
Points that aren’t all on the same line
Intersection
2 or more geometric figures intersect if they have 1 or more points in common
Distance
The distance between points A&B is the absolute value of the difference between their coordinates
(In geometry),A rule that is accepted without proof is called a…
Postulate or axiom
If B is between A and C, then…
AB+BC=AC (lengths)
If AB+BC=AC, then…
B is between A&C
Lengths are _____
Segments are ____
Equal
Congruent
Angle
Two Rays that are connected at the same point (vertex)
Acute angle
Angle measuring 0-90 degrees
Right angle
Angle that is exactly 90 degrees
Perpendicular lines
Lines that intersect to make all right angles
Obtuse angles
Angles that measure 90-180 degrees
Straight angle
Angles that are exactly 180 degrees
Congruent angles
Angles that have the same degree
Angle bisector
A ray that divides the angle directly in the center
Adjacent angles
Angles that share a side & vertex
Complementary angles
2 angles that add up to 90 degrees
Supplementary angles
2 angles that add up to 180 degrees
Linear pair
Adjacent angles who’s non comon sides are opposite rays
Vertical angles
If their sides form 2 pairs of opposite Rays
Theorem to solve right triangles
Hypotenuse^2 = leg^2 + leg^2
Triangle inequality theorems
- the longest side is across from the biggest angle
- the sum of any 2 leg this is > 3rd side
Converse of the Pythagorean theorem
- if the square of the length of the longest side of a triangle is equal to the sum of the squares of the lengths of the other two sides, then the triangle is a right triangle
- if c^2 = a^2 + b^2, then triangle ABC is a right triangle
A line can be names using 3 points
Never
2 points are collinear
Always
If 2 lines intersect, their intersection is a point
Sometimes
If 2 different distinct lines intersect, their intersection is a point
Always
3 points are collinear
Sometimes
2 lines that do not intersect are skew
Sometimes
Points A, B, and C are coplanar
Always
2 planes can intersect in a point
Never
3 collinear points determine a plane
Never
Line EF intersects plane m at exactly 2 points
Never
Parallel lines are _____
Skew lines are _____
Flat
Twisted
Distinct
Different
