# Important Things to Know About Circle with Cuemath

Right from our childhood, we all have been taught about the different geometrical figures this will include triangles, squares, rectangles, circles, etc. In higher studies when the geometry concept is introduced, in-depth knowledge about a circle is given to the students. A circle is the special kind of ellipse that has zero eccentricity and also has two coincident foci. The figure of the circle is drawn in such a way the distance from the canter is the same from all directions. The distance from one outer point to another outer point is known as diameter and the distance from the center of a circle to the outer line of the circle is known as radius. Students are also taught about the area of circle.

A circle is a 2D shape that is measured in the terms of radius. It will divide the plane into two parts i.e. exterior region and interiors region. This figure has both area and perimeter which can be determined using a formula. It is a closed two-dimensional figure that will help in setting out all the points in equidistance to the center point of the circle. Each line that passes through the circle will form reflection symmetry and even it has rotational symmetry from every angle.

There are so many objects that signify the real shape of a circle in real life. Some of them are bangles, coins, wheels, buttons, CDs, rings, hula hoops, dartboard, car starring, and many more. Seeing so many circular things around us helps us to understand the importance of a circle. Even the planet on which we live is a huge circle which is tilted somewhat on its axis.

It is very easy for a student to draw a circle on paper. Either they can take the help of a bangle to draw a circle. If they want more accuracy in the work, they can take the help of the compass. Now they can measure the radius that they want of the circle. After measuring that, they can place the pin side of a compass on the page and carefully draw a circle. It is a great way to drawing the perfect shaped circle.

## A circle has different parts based on its positions. Here is the list of some along with their features. Let’s have a look at them

• Annulus: It is the region that is bounded by two concentric circles.
• Arc: The connected curve of a circle
• Sector: It is a region that is bounded by an arc and two radii
• Segment: It is a region that is bounded by an arc and a chord. Please note a fact that segments do not have any centre point.
• Center: The midpoint of the circle
• Chord: A line segment whose endpoint is lying on the circle
• Diameter: It is the largest chord of the circle that has both endpoints on the circle.
• Radius: A line segment that connects one endpoint of the circle with the center.
• Secant: A straight line that will cut the circle in half. Even some call it an extended chord.
• Tangent: It is a straight line that touches the circle at a single point.

A line segment that connects the center of the circle to any point of the circle’s outer line is known as Radius. It is denoted by “R” or “r”. The line segment starts from one end of the circle and ends at a second end. Mostly it is two times of radius. Diameter is denoted by “d”. To calculate radius if the diameter is given formula is r= d/2.

The area of a circle is the amount of space occupied by the circle. The formula for calculating the area of a circle is ∏r2 whereas circumference is the distance that is around the circle. It is like the perimeter of the figure. It can be calculated with the formula i.e. C= 2∏r or ∏d.

If you are interested in learning more about the concepts of circles, Cuemath is a great online platform to polish the concepts and make them clear in mind.