Area Related to Circles

Area Related to Circles - Sub Topics

  • What is a Circle?
  • Parts of a Circle
  • Ring of a Circle
  • Area of a Circle
  • Formulas Related to Area of a Circle
  • The reading material provided on this page for Area related to Circles is specifically designed for students in grades 9 to 12. So, let's begin!

    What is a Circle?

    A circle is a two-dimensional geometric shape that is perfectly round and consists of all the points in a plane that are equidistant from a fixed centre point.

    Parts of a Circle

    In addition to the well-known parts of a circle such as the radius, diameter and circumference, there are other important components to be aware of. Let's explore some additional parts of a circle.

    Radius of a Circle

    The radius of a circle is a line segment that connects the centre of the circle to any point on its circumference. It is denoted by the letter "r".

    radius of circle

    Diameter of a Circle

    The diameter of a circle is a line segment that connects two points on the circumference, passing through the centre of the circle.

    Diameter = 2 x radius

    diameter of circle

    Circumference of a Circle

    The circumference of a circle is the distance around its outer boundary.

    Circumference = 2 π r

    circumference of circle

    Chord of a Circle

    A chord is a straight-line segment that connects two points on the circumference of the circle. It does not necessarily pass through the centre.

    chord of circle

    Tangent of a Circle

    A tangent is a straight line that touches the circle at only one point, known as the point of tangency.

    tangent of circle

    Arc of a Circle

    An arc is a portion of the circumference of a circle. It is measured in terms of degrees and represents a specific angle (central angle). There are two types of arcs: 1) Major arc, 2) Minor arc

    arc of circle

    Sector of a Circle

    A sector is a region enclosed by two radii of the circle and the corresponding arc between them. It is similar to a slice of a pie. There are two types of sectors: 1) Major sector, 2) Minor sector

    sector of circle

    Segment of a Circle

    A segment of a circle refers to the region bounded by an arc and the chord that connects its endpoints. There are two parts of segments:

    a) Major segment b) Minor segment

    segment of circle

    Ring of a Circle

    A ring refers to the region between two concentric circles. It can be visualized as a circular band with a defined width. The outer circle represents the larger radius while the inner circle represents the smaller radius.

    ring of circle

    Area of a Circle

    The area of a circle is the amount of space inside the circle. It is calculated using the formula: A = πr2, where A is the area, π is a mathematical constant (approximately equal to 3.14) and r is the radius of the circle (the distance from the centre of the circle to its edge). The unit of measurement for the area is square units, such as square inches or square centimetres.

    area of circle

    Example: A circle has a radius of 5 cm. Find the area of the circle.

    Solution: To find the area of a circle, we use the formula

    A = πr2

    In this example, the radius of the circle is 5 cm, so we plug in the values and get:

     A = π x 52

    = 25 π           ( π = 3.14)

    = 25 x 3.14

    = 78.54 cm2

    So, the area of the circle is 78.54 cm2.

    Formulas Related to Area of a Circle

    formulas for area of circle

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