Understanding the Basics of Circles | Definitions, Properties, and Formulas

circle

A circle is a two-dimensional geometric figure that is perfectly round and symmetrical

A circle is a two-dimensional geometric figure that is perfectly round and symmetrical. It is defined as a set of points on a plane that are equidistant from a fixed point known as the center. The distance between the center of the circle and any point on its boundary, known as the circumference, is constant and called the radius.

Here are some key terms associated with circles:

1. Center: The fixed point in the middle of the circle from which all points on the circumference are equidistant.

2. Radius: The distance between the center of the circle and any point on its boundary. It is denoted by “r”.

3. Diameter: A line segment passing through the center of the circle and connecting two points on the circumference. It is twice the length of the radius.

4. Circumference: The distance around the outer boundary of the circle. It can be calculated using the formula C = 2πr, where “C” represents the circumference and “π” is a constant approximately equal to 3.14159.

5. Pi (π): A mathematical constant representing the ratio of a circle’s circumference to its diameter. Its value is approximately 3.14159. Pi is an irrational number, meaning it cannot be expressed as a simple fraction.

6. Arc: A curved part of the circle’s circumference.

7. Sector: The region enclosed by two radii and the corresponding arc of a circle.

8. Chord: A line segment connecting two points on the circumference of a circle.

9. Tangent: A line or line segment that touches the circle at exactly one point and is perpendicular to the radius at that point.

Circles have various properties and formulas associated with them, including area, arc length, and different relationships between angles and chords. Understanding these concepts can be useful in solving mathematical problems and real-world applications that involve circles.

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