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Fennville Geo Unit 1
review of key ideas for unit 1 geometry
Term | Definition |
---|---|
point | names a location. represented by a dot. |
line | straight path through two or more points that extends forever. |
segment | part of a line consisting of two endpoints and all points between them. |
ray | part of a line that starts at an endpoint and extends forever in one direction. |
angle | formed by two rays with the same endpoint. |
acute angle | angle that measures greater than zero and less than 90 degrees |
right angle | angle that measures exactly 90 degrees |
obtuse angle | angle that measures greater than 90 degrees and less than 180 degrees |
straight angle | angle formed by two opposite rays and measures exactly 180 degrees |
angle bisector | a ray that divides an angle into two congruent angles. a ray that splits an angle in half. |
bisect | to cut in half |
collinear points | points that lie on the same line |
non-collinear points | three or more points that do not lie on the same line |
coplanar | points that lie on the same plane |
congruent angles | angles which have the same measure |
complementary angles | two angles that add to 90 degrees |
supplementary angles | two angles that add to 180 degrees |
distance | absolute value of the difference of the coordinates of two points on a number line |
linear pair of angles | two adjacent angles that form a straight angle or line. |
adjacent angles | two angles with the same vertex that share a side but do not share any interior points. |
non-adjacent angles | two angles that are not adjacent. |
plane | flat surface that has no thickness and extends forever; formed by three non-collinear points |
vertical angles | two non-adjacent angles formed by two intersecting lines. |
midpoint of a segment | point exactly in the middle of a segment. |
reflection | transformation across a line (flip) which produces congruent figures with opposite orientations |
rotation | transformation about a point (turn) which produces congruent figures with the same orientation |
translation | transformation in which all points move the same distance in the same direction (slide) which produces congruent figures with the same orientation |
transformation | a change in the position, size, or shape of a figure. |
opposite rays | two rays that have a common endpoint and form a line. |
AC | by the segment addition postulate, when point B is between points A and C on segment AB, AB + BC = |
ABD | by the angle addition postulate, measure of angle ABC + measure of angle CBD = measure of angle |