(1) From the figure, identify
(a) The center of circle
Ans. The center of the circle in the given figure is point O.
Ans. The three radii in the given figure are – OA, OB and OC
(c) A diameter
Ans. A diameter in the given figure is AC
(Note – The diameter is the length of the line through the center that touches two points on the edge of the circle)
(d) A chord
Ans. A chord in the given figure is ED.
(Note – The chord of a circle is the line segment joining any two points on the circumference of the circle)
(e) Two points in the interior
Ans. The two points in the interior of the given figure are : Point O & Point P
(f) A point in the exterior
Ans. A point in the exterior of the circle is point Q.
(g) A sector
Ans. A sector in the given circle is AOB (the blue shaded portion of the given figure).
(Note – A sector is the portion of a disk enclosed by two radii and an arc in a circle)
(h) A segment
Ans. A segment in the given figure is ED (the red shaded portion of the given figure).
(Note – a segment is a region of a circle which is “cut off” from the rest of the circle by a secant or a chord)
(a) Is every diameter of a circle also a chord?
Ans. Yes, every diameter of a circle is also a chord.
In fact, diameter is also called as the longest chord of the circle.
(b) Is every chord of a circle also a diameter?
Ans. No, every chord of a circle is not a diameter because diameter only passes through the center while for chord it is not necessary.
Draw any circle and mark
(a) its centre
(b) a radius
(c) a diameter
(d) a sector
(e) a segment
(f) a point in its interior
(g) a point in its exterior
(h) an arc
(4) Say true or false:
(a) Two diameters of a circle will necessarily intersect.
Reason – All the diameters in a circle have to pass through the center of the circle. Therefore, diameters of a circle will necessarily intersect at its center.
(b) The center of a circle is always in its interior.
Ans. True, the center of a circle is always in its interior