This document provides definitions and examples of geometric terms related to circles. It defines a circle as all points equidistant from a center point, and defines related lines and segments including the radius, diameter, chord, tangent, and secant. Examples are given of each term, such as a radius being the segment from the center to the circle, a diameter passing through the center, and a tangent touching the circle at one point. The purpose is to teach students the key elements of circles for a geometry lesson.

1. A
D
C
B
F
E
H
G
Republic of the Philippines
Department of Education
Region VI – Western Visayas
Division of Passi City
EFRAIM M. SANTIBAÑEZ NATIONAL HIGH SCHOOL
Sto. Tomas, Passi City
CIRCLES
Module 1
Lesson 1 – Identifying a circle, the lines, segments and angles
associated with it.
What are you expected to learn?
1. Define a circle
2. Define and show examples of the lines and segments associated with circles.
Definition of Terms
 A circle is defined as the set of all points that are at the same distance from a given point in the
plane.
 The fixed point is called the center.
 Radius of a circle is a segment whose endpoints are the center and a point on the circle.
 Chord is a segment whose endpoints are the points on the circle
 Diameter is a segment whose endpoints are points on the circle and it passes through the
center.
 Tangent is a line that intersects a circle at one point.
 Secant is a line that intersects a circle at two points.
Circles are named using its center. Thus, the figure on the right is called circle A
or in symbol ⊙ 퐴.
퐴퐵 Is a radius
퐸 퐹 is a chord
퐸 퐹 is a secant
퐷 퐻 is a tangent
퐶 퐺 is a diameter