Chapter 1: Geometry Notation- Anderson
length of a segment
MN=12 How far from M to N
acute angle
less than 90 degrees
perpendicular
lines, rays, segments, or planes that intersect and make right angles
parallel
lines, rays, segments, or planes that never intersect when extended forever (in algebra they have the same slope)
straight angle
180 degrees
obtuse angle
more than 90 degrees less than 180 degrees
angle addition posturate
part+part=whole
non-coplanar
points or lines that could NOT lie on the same plane
coplanar
points or lines that could lie on the same plane
non-collinear
points that could NOT have a line drawn through them.
collinear
points that could all lie on the same line
right angle
90 degrees
plane
a flat surface that goes on forever and contains points, lines, and rays
point
a location in space
midpoint
a point that divides a segment into two congruent segments
supplementary
angles that add up to 180 degrees
complementary
angles that add up to 90 degrees
congruent angles
angles that have the same measure. It is shown by having tick marks through the angle to show congruency
segment bisector
another name for a midpoint
congruent
equal
measure of an angle
how much an angle opens up (measured in degrees)
segment addition posturate
if 3 points (ABC) are collinear and B is in between A and C then AB+BC=AC
congruent segments
segments that have the same measure or length. shown by using tick marks. a segment with one tick mark is equal to another segment with only one tick mark
ray
straight path that goes forever in one direction. it has on end point
line
straight path that goes forever in two directions
line segment
straight path that has 2 end points
angle
the interior space when two rays, lines or segments intersect. the point where they intersect is the vertex.
vertical angles
they are across from each other and share the same line. these angles are always congruent
adjacent angles
two angles that share the same side
opposite rays
two rays that make a line/straight angle