# Geometry Chapters 1-2

## 21 terms

### angle

a figure formed by two rays with a common endpoint

### vertex

the point of intersection of two sides of any angle or figure

### acute angle

an angle that measures less than 90 degrees (smaller than an L)

### right angle

an angle that measures exactly 90 degrees (same as an L)

### obtuse angle

an angle whose measure is greater than 90 degrees but less than 180 degrees (larger than an L)

### straight angle

an angle that measures 180 degrees (lays flat)

### congruent angles

angles with equal measures

two angles that share a common side and a common vertex; they are NEXT to each other

### vertical angles

opposite, non-adjacent angles formed by two intersecting lines; always congruent

### complementary angles

two angles whose measures have a sum of 90 degrees

### supplementary angles

two angles whose measures have a sum of 180 degrees

### linear pair

two adjacent angles whose non-shared, opposite sides form a line

### angle bisector

A line, segment, or ray that divides an angle in half, forming two congruent angles

### collinear

points that lie in a straight line

### intersection

the point where two lines or planes meet

### endpoint

a point at the end of a segment or ray

### parallel lines

lines in the same plane that never intersect

### congruent

equal figures having the same shape and the same size

### hypothesis

the "if" part of a conditional statement

### conclusion

the "then" part of a conditional statement

### conditional statement

an "if-then" statement