# Polygons

## 25 terms · vocabulary over chapter 6 and chapter 9.

### polygon

a closed plane figure bounded by straight sides

### area

the number of square units needed to cover a flat surface

### perimeter

the distance around a figure

a four-sided polygon

### consecutive

angles or sides that are next to each other

### diagonal of a polygon

segment that connects any two nonconsecutive sides together in a polygon

### regular polygon

a polgyon that has all equal sides and equal angles

### concave

when a diagonal can be drawn outside the polygon

### convex

all diagonals can be drawn within the polygon

### parallelogram

2 sets of parallel opposite sides

### trapezoid

exactly one pair of parallel opposite sides

### circle

a round figure containing no straight segments

### square

a polygon that is a combination of a rhombus and a rectangle

4 right angles

### rhombus

four equal sides, opposite angles are congruent

3 sided polygon

### circumference

distance around a circle

the distance from the center of the circle and any point on the circle

### diameter

the distance across a circle through its center

### apothem

a segment that is drawn from the center of a regular polygon perpendicular to a side of the polygon

### central angle of a regular polygon

The angle whose vertex is the center and whose sides contain two consecutive vertices of the polygon.

### composite figure

any figure made up of two or more geometric shapes

### isosceles trapezoid

a trapezoid with congruent legs

### bases of a trapezoid

the pair of parallel opposite sides

### Flickr Creative Commons Images

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