# Math Vocabulary

### A Quick Resource Guide

## Rotation

A Rotation is a transformation that turns a figure about a fixed point. See this for more help.

## Circumscribed circles

In geometry, the

Below is a video tutorial explaining properties of circumscribed circles and how they differ from inscribed circles.

**circumscribed circle**or**circumcircle**of a polygon is a circle which passes through all the vertices of the polygon. The center of this circle is called the**circumcenter**and its radius is called the**circumradius**.Below is a video tutorial explaining properties of circumscribed circles and how they differ from inscribed circles.

## Angles

Type of Angle Description

Acute Angle an angle that is less than 90°

Right Angle an angle that is 90° exactly

Obtuse Angle an angle that is greater than 90° but less than 180°

Straight Angle an angle that is 180° exactly

Reflex Angle an angle that is greater than 180°

Check out this site for more information and a cool tool for experimenting with angle sizes.

## Perpendicular lines

When two lines are perpendicular, the slope of one is the negative reciprocal of the other. If the slope of one line is m, the slope of the other is -1/m. Click here for more help and a tool for experimenting with lines.

## Rhombus

A rhombus is a polygon with two sets of parallel sides and four congruent sides. Look here for additional information.