# geometry terms

## 48 terms

### point

a location in space that has no size or shape

### line

a set of points that go forever in two directions

### line segment

a part of a line thatt has a begining and an end that are both called end points

### plane

a flat surface that goes forever in all directions

### congruent

exactly the same size and shape

### angle

a figure formed when two rays have a common end point

### vertex

common endpoint of the two rays that form the angle.

### ray

a part of a line that has one end point and goes forever

### acute angle

an angle that measures less than 90 degrees and more than 0 degrees

### right angle

an angle that measures exactly 90 degrees

### obtuse angle

an angle that measures more than 90 degrees but less than 180 degrees

### straight angle

an angle that measures exactly 180 degrees

are two angles that share a common ray- they are right next to eachother

### vertical angles

formed when 2 lines intersect- they are the pair of angles that are opposite each other. they are concruent

### complementary angles

Angles whose measures add up to 90 degrees

### supplementary angles

angles whose measures add up to 180 degrees

### perpedicular lines

lines that intersect to form right angles

### parallel lines

two lines on the same plane that will never intersect

### transversal line

a line that intersects two parallel lines

### alternate interior angles

between the parallel line and on opposite side of the transversal, and are not adjacent.

### alternate exterior angles

outside of the parallel line and on opposite sides of the trasversal, are not adjacent. They are congruent

### corresponding angles

ocated in the same position on each of the parallel lines/ are congruent. below the parallel line on the same side of the transversal

### circle

the set of all points in a plane that are the same distance from a fixed point called the center

### chord

a line segment whose endpoints are on the circle

a line segment from the center of the circle to a point on the circle.

### diameter

a line segment that passes through the center of the circle whose endpoints are on the circle

### arc

a part of a circle

### polygon

a closed plane figure made up of line segments that meet at their end points to form vertices

a polygon with four sides

### pentagon

a 5 sided polygon

### hexagon

a six sided polygon

### octagon

eight sided polygon

### decagon

a ten sided polygon

### regular polygon

a polygon that has all sides congruent (equilateral) and all angles congruent (equiangular)

### equilateral triangle

a triangle with 3 congruent sides and 3 congruent angle

### isosceles triangle

a triangle with at least 2 congruent sides and angles

### scalene triangle

a triangle that has no congruent sides

### acute triangle

a triangle with 3 acute angles

### right triangle

has only 1 right angle and 2 acute angles

### obtuse triangle

a triangle with one obtuse angle and 2 acute

### daigonal

a line segment that connects two non consecutive vertices of a polygon

### trapezoid

a quadrilatera with one pair of parallel sides

### parallelogram

a quadrilateral with 2 pair of parallel sides and opposite sides congruent

### rectangle

a qudrilateral and a paralleogram with 2 pair of parallel sides with 2 sides congruent and 4 right angles

### rhombus

a quadrilateral that is a parallelogram that has 2 pair of parallel sides and has 4 congruent sides

### square

a quadrilateral with 2 pair of parallel sides, 4 congruent sides and four right angles

### kite

has exactly 2 pair of congruent adnacent sides

### nonagon

a nine sided polygon