# CH 9 Vocabulary

## 31 terms

### Angle

Two rays with a common endpoint.

### Side

A ray that is part of an angle.

### Vertex

The common endpoint of an angle.

### Degree

The most common unit of measure for angles.

Exactly 90°

Less than 90°

### Obtuse Angle

Between 91°and 179°

Exactly 180°

### Vertical Angles

Opposite and Congruent Angles.

### Congruent Angles

Angles with the same measure.

### Complementary Angles

Two (or more) angles that have the sum of 90°.

### Supplementary Angles

Two (or more) angles that have the sum of 180°.

### Acute Triangle

All 3 angles are acute angles.

### Right Triangle

One angle is a right angle.

### Obtuse Triangle

One angle is an obtuse angle.

### Line Segment

The side of the triangle.

### Congruent Segments

Line segments that have the same length.

### Scalene Triangle

No congruent sides.

### Isosceles Triangle

At least two congruent sides.

### Equilateral Triangle

All 3 congruent sides.

### Sum of Angles in a Triangle

Angles add up to equal 180°.

A figure with four sides and four angles.

### Rectangle

Opposite sides congruent, all angles are right angles, opposite sides parallel

### Square

All sides congruent, all angles are right angles, opposite sides parallel

### Parallelogram

Opposite sides congruent, opposite sides parallel, opposite angles congruent

### Rhombus

All sides congruent, opposite sides parallel, opposite angles congruent

### Trapezoid

Exactly one pair of opposite sides parallel

### Sum of angles in a quadrilateral

The angles add up to equal 360°.

### Similar Figures

Figures that have the same shape but not necessarily the same size.

### Congruent Figures

Figures that have the same shape and same size.

### Corresponding Sides

The sides of congruent or similar figures that match.