# Basic Geometry Terms

## 27 terms

### Point

Location in space

### Line

Set of all points that extend in opposite directions forever

### Plane

A flat surface that extends forever in all directions

### Line Segment

Part of a line with two endpoints

### Ray

Part of a line with one endpoint that extends forever in one direction

### Angle

Two rays that intersect at their endpoints

### Vertex

The intersection of the two rays of an angle

### Protractor

Tool that measures angles

### Acute Angle

Angle that measures less than 90 degrees

### Right Angle

Angle that measures 90 degrees

### Obtuse Angle

Angle that measure greater than 90 degrees

### Straight Angle

Angle that measures 180 degrees

### Complementary Angles

Angles whose sum is 90 degrees

### Supplementary Angles

Angles whose sum is 180 degrees

Angles that share a ray but do not overlap

### Triangle

A polygon with three sides and three angles

### Congruent Figures

Figures with the same shape and same size

### Equilateral Triangle

Triangle with three congruent sides

### Isosceles Triangle

Triangle with two congruent sides

### Scalene Triangle

Triangle with no congruent sides

### Equiangular Triangle

Triangle with three congruent angles

### Right Triangle

Triangle with one angles measuring 90 degrees

### Acute Triangle

Triangle with three angles measuring less than 90 degrees

### Obtuse Triangle

Triangle with one angle measuring greater than 90 degrees

### Collinear

Points on the same line

### polygon

a closed figure made up of line segments called sides

### regular polygon

a polygon with all congruent angles and sides