# Circumference and Circle

- Author:
- Jorge Cássio

- Topic:
- Circle, Unit Circle

## Move point P.

## Analysis 1

What do you notice about point P?

## Definitions and Elements

**Circumference**is the set of points of a plane whose distance to a certain point (

**center**) of that plane is equal to a certain (non-zero) distance. This distance is the

**radius**of the circumference.

## Geometric Representation

## Algebraic Representation

Consider a plane , a point O of and a distance r,
Where represents the circumference of center O and radius r.

## Move Point X.

## Position of the point and circumference

Consider a point X and a circumference ,
X is internal to
X is within ,

## Chord, Diameter and Radius

## ARC AND SEMICIRCUNFERENCE

## CIRCLE - Linguistic Representation

**Circle**is the set of points of a plane whose distance to a certain point (

**center**) of that plane is less than or equal to a certain (non-zero) distance.

## CIRCLE - Figural representation

## Algebraic Representation

Center circle A and radius r