Name the following parts of the given circle: Radius

Given, We know that the radius is the distance between the centre to any point on the boundary of the circle. All the radii of a circle are equal in measure. OA ¯ = OB ¯ = OC ¯ = r Therefore, the required radius are OA , OB , OC .

Name the following parts of the given circle: Diameter

Given, We know that a line segment with both its endpoints on the boundary of the circle and passing through the centre of the circle is called the diameter of the circle. From the given figure, line BC ¯ is the diameter of a given figure. Therefore, the diameter of a given figure is BC .

Name the following parts of the given circle: Chord

Given, We know that a line segment whose endpoints lie on the circle is called a chord of the circle. The diameter of a circle is the longest chord of the circle. From the above figure, the chords are PQ , BC . Therefore, the required chords are PQ , BC .

Name the following parts of the given circle: Semi-circle

Given, We know that the diameter of a circle divides the circle into two equal parts. Each part is called a semi-circle. We can also say that half of a circle is called a semicircle. In the above figure, BQC and BRC represent two semi-circles. Therefore, the required semicircles are BQC and BRC .