# vocabulary

## area

the size of a surface

## perimeter

the distance around a two-dimensional shape.

## exterior angle

the angle between any side of a shape, and a line extended from the next side.

## dilation

where the polygon grows or shrinks but keeps the same overall shape.

## scale factor

a number which scales, or multiplies, some quantity.

## Corresponding Angles

When two lines are crossed by another line

## Line of Symmetry

does not have to be up-down or left-right, it can be in any direction.

is less than 90°

## Obtuse Angle

is more than 90° but less than 180°

## Perimeter

is the distance around a two-dimensional shape.

## Vertical Angles

the angles opposite each other when two lines cross.

## Congruent

If one shape can become another using Turns, Flips and/or Slides, then the shapes are Congruent

## Trapezoid

is a 4-sided flat shape with straight sides that has a pair of opposite sides parallel

The distance from the center to the edge of a circle

It is half of the circle's diameter.

## Diameter

A straight line going through the center of a circle connecting two points on the circumference

## Surface Area

The total area of the surface of a three-dimensional object

## Volume

The amount of 3-dimensional space an object occupies. Capacity.