Good morning teachers and students! Our first discussion of diagrams will be an **Element of Circle** Diagram for Junior high school students. Our team (in 101diagrams.com) consists of people who have a competence in their specific education field. Including engineering field, science and math department, biology college student, English literature major student and many more. So in this site we will give you hundreds of diagram source for educational purpose. Let us begin.

A **circle** is a curved line whose both end points meet eachÂ other and in which all points are *equidistant* (at the sam distance) from a given point. Look at the first picture above, the points A, B and C are the same distance from point O. This point O is called the **center of the circle**.

To understand the figure above , you can see the following description:

- The point O is called the
**center of the circle** - The lines OA, OB, OC are called
**radii(r)**(singular:radius) - The line AC called a
**diameter (d)**. The diameter’s length = 2 times the length of the radius - The straight line FE is called a
**chord** - The curves lines AB and FE are called
**arcs**. - The region bounded by 2 radii and an arc, such as that bounded by OA, OB, and the arc of AB, is called a
**sector** - The region bounded bythe chord FE and the arc FE is called a
**segment**. - The line OD, called an
**aphotem**, is the shortest distance between the chord and the circle’s center.

In the left figure above, the curved line PQ is called an arc. The chord PQ divides the circle into two parts, i.e:

1. a** minor arc**, which is the arc PQ whose length is *less than* half of the circumstance.

2. a **major arc**, which is the arc PQ whose length is *more than* half of the circumstance.

And so in the right figure above, the region bounded by the radii OA, OB and arc AB is called a **sector**. A sector with an area of less then half the circle’s area called *minor sector. *And then a sector with an area of more than half the circle’s area is called a *major sector.*