Basic Geometrical Ideas
Question 1.
From the figure, identify:
(a) the centre of circle
(b) three radii
(c) a diameter
(d) a chord
(e) two points in the interior
(f) a point in the exterior
(g) a sector
(h) a segment
Solution:
(a) O is the centre of the circle.
(b) OA, OB and OC are three radii of circle.
(c) AC is a diameter of circle.
(d) ED is a chord of circle.
(e) Points O and P are in the interior of circle.
(f) Point Q is in the exterior of circle.
(g) OAB is a sector of circle.
(h) Shaded region in the interior of a circle enclosed by a chord ED.
Question 2.
(a) Is every diameter of a circle also a chord?
(b) Is every chord of a circle also a diameter?
Solution:
(a) Yes, a diameter is the longest chord.
(b) Not always.
Question 3.
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
Solution:
Draw any circle and its various parts are as under :
(a) Its centre is O.
(b) Its radii are OA, OB and OC.
(c) Its diameter is AOC.
(d) Its sector is OAB.
(e) Shaded region in the interior of a circle enclosed by a chord PQ.
(f) M is a point in its interior.
(g) N is a point in its exterior.
(h) BC is an arc.
Question 4.
Say true or false:
(a) Two diameters of a circle will necessarily intersect.
(b) The centre of a circle is always in its interior.
Solution:
(a) True, because each diameter passes through the centre of a circle.
(b) True.