NCERT Solutions for Class 6  
                                                        Maths 
                                   Chapter 4 – Basic Geometrical Ideas 
                
               Exercise 4.6 
                
               1. From the figure, identify: 
                                                                 
               i. The centre of circle 
               Ans: The centre of a circle is a point that is equidistant from all the points on 
               the circumference of the circle. It is the point that is in the middle of the circle. 
               The centre of the circle in the given figure is point O. 
                
               ii. Three radii 
               Ans: The radii are the distance of any point on the circumference of the circle 
               from the centre of the circle. It is also half of the diameter of the circle. 
               The three radii of the circle in the given figure are OA, OB, and OC. 
                
               iii. A diameter 
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               Ans: The diameter is the longest line that connects any two points on the 
               circumference of the circle. The diameter of any given circle will always pass 
               through its center. Diameter is the longest chord in a circle. The diameter is 
               twice the radius in the circle. 
               The diameter of the circle in the given figure is AC. 
                
               iv. A chord 
               Ans: A chord is a line that connects any two points on the circumference of the 
               circle. A chord divides a circle into two unequal parts. The diameter is the 
               longest chord in a circle that divides the circle into two equal parts.  
               The chord of the circle in the given figure is ED. 
                
               v. Two points in the interior 
               Ans: Points that lie within the circumference of the circle are known as the 
               interior points. The centre is a kind of an interior point. 
               The two interior points in the circle in the given figure are O and P . 
                
               vi. A point in the exterior 
               Ans: Points that lie outside the circumference of the circle are known as the 
               exterior points. 
               The exterior point outside the circle in the given figure is Q. 
                
               vii. A sector 
               Ans: A sector is that part of the circle that lies between the two radii and an arc 
               of the circle. The sector subtends any angle at the centre of the circle. 
               The sector of the circle in the given figure is OAB. 
                
               viii. A segment 
               Ans: A segment is that part of the circle that is formed by the chord. In other 
               words, the segment is formed by the chord dividing the circle.  
               The segment of the circle in the given figure is ED. 
                
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               2. (a) Is every diameter of a circle also a chord? 
               Ans: The diameter is the longest line that connects any two points on the 
               circumference of the circle. The diameter of any given circle will always pass 
               through its center. The diameter is twice the radius in the circle. 
               A chord is a line that connects any two points on the circumference of the circle. 
               A chord divides a circle into two unequal parts.  
               The diameter is the longest chord in a circle that divides the circle into two 
               equal parts.  
               Therefore, we can conclude that every diameter of a circle is also a chord. 
                
               (b) Is every chord of a circle also a diameter? 
               Ans: A chord is a line that connects any two points on the circumference of the 
               circle. A chord divides a circle into two unequal parts.  
               The diameter is the longest line that connects any two points on the 
               circumference of the circle. The diameter of any given circle will always pass 
               through its center. The diameter is twice the radius in the circle. 
               The diameter is the longest chord in a circle that divides the circle into two 
               equal parts.  
               Therefore, the diameter is a type of chord. 
               However, not all chords are diameters. This is because not all chords pass 
               through the centre. 
               Therefore, we can conclude that not every chord of a circle is a diameter but 
               every diameter is a chord of a circle.  
                
               3. Draw any circle and mark: 
               (a) Its centre 
               Ans: The centre of a circle is a point that is equidistant from all the points on 
               the circumference of the circle. It is the point that is in the middle of the circle. 
               The centre of the circle in the given figure is point O. 
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               (b) A radius. 
               Ans: The radius is the distance of any point on the circumference of the circle 
               from the centre of the circle. It is also half of the diameter of the circle. 
               A circle possesses an infinite number of radii.  
               The radius of the circle is OA. 
                                                               
                
               (c) A diameter  
               Ans: The diameter is the longest line that connects any two points on the 
               circumference of the circle. The diameter of any given circle will always pass 
               through its center. Diameter is the longest chord in a circle. The diameter is 
               twice the radius in the circle. 
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