# Math vocabular CHAPTER NINE!-

## 26 terms

### Angle

Two rays with a common endpoint from an angle.

### Side

A ray that is part of an angle.

### Degrees

A unit for measuring angles.

### Vertex

The common endpoint of two rays that form an angle.

### Right Angle

An angle that measures 90 degrees

### Acute Angle

an angle greater than 0 degrees but less than 90 degrees

### Obtuse Angle

an angle that measures greater than 90 but less than 180

Exactly 180

### acute triangle

A triangle which each angle measures mess then 90°

### Right angle

An angle that measure exactly 90°

### Obtuse angle

An angle that measures more that 90° but less than 180°

### line segment

Part of a line containing two endpoints all the points between them

### Congruent angles

Angles that have the same measure

### Scalene triangle

A triangle with no congruent sides

### Isosceles triangle

A triangle with at least two congruent sides

### Equilateral

A triangle having all three sides congruent and all three angles congruent.

### Vertical

Opposite angles formed by the intersection of two lines.

### Congruent angles

Having the same measure

### Supplementary angles

Two angles are supplementary if the sum of their measures is 180°.

### Complementary angles

Two angles are complementary if the sum of their measures is 90°

A polygon having four sides

### Rectangle

A polygon with four right angles

### Square

A parallelogram with four congruent sides and four right angles.

### Parallelogram

A quadrilateral with both pairs of opposite sides parallel and congruent.

### Rhombus

A parallelogram with four congruent side

### Trapezoid

A quadrilateral with exactly one pair of parallel opposite sides.