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Geometry Chapter 1 K
Vocabulary
Term | Definition |
---|---|
undefined term | a basic figure not defined in terms of other figures |
point | an undefined term in Geometry that has no size |
line | a set of points extending infinitely in two directions |
plane | a flat surface with no thickness that extends forever |
collinear | points on the same line |
coplanar | points on the same plane |
segment | part of a line with 2 endpoints |
endpoint | one end of a segment or the starting place for a ray |
ray | a set of points extending infinitely in 1 direction |
opposite rays | 2 rays with a common endpoint that form a line |
postulate | a statement accepted as true without proof |
coordinate | a point that corresponds to a number |
distance | the absolute value of the difference in the coordinates |
length | the distance between 2 points |
congruent segments | 2 segments with the same length |
construction | a way to creating a more precise figure, in Geometry we use a compass and straightedge |
between | B is between A and C if and only if they points are collinear and AB + BC = AC. |
midpoint | a point that divides a segment into 2 congruent parts |
bisect | to cut into 2 congruent parts |
segment bisector | any ray, segment, or line that intersects a segment at its midpoint |
angle | 2 rays that have a common endpoint |
vertex | the common endpoint shared by the 2 rays of an angle |
interior of an angle | the set of all points between the sides of an angle |
exterior of an angle | the set of all points outside an angle |
measure | the size of an angle, in degrees |
degree | 1/360 of a circle |
acute angle | an angle less than 90 degrees |
obtuse angle | an angle greater than 90 degrees |
right angle | an angle that measures exactly 90 degrees |
straight angle | an angle that measure 180 degrees |
congruent angles | 2 angles with the same measure |
angle bisector | any line, segment, or ray that divides an angle into 2 congruent parts |
adjacent angles | 2 angles that share a common side and vertex |
linear pair | 2 adjacent angles that form a straight line |
complementary angles | a pair of angles that have a sum of 90 degrees |
supplementary angles | a pair of angles that have a sum of 180 degrees |
vertical angles | 2 angles whose sides form opposite rays |
coordinate plane | a plane that is divided into 4 regions by a horizontal and vertical axis |
leg | the sides of a right triangle that form the right angle |
hypotenuse | the side of a right triangle that is opposite the right angle |
transformation | the change in the position, size, or shape of a figure |
preimage | the original figure in a transformation |
image | the new figure in a transformation |
reflection | (a flip) a transformation across a line called the line of reflection |
translation | (a slide)a transformation in which all the points of a figure move the same direction in the same distance |
rotation | (a turn)a transformation about a point P called a center of rotation |