RBSE Class 6 Maths Notes Chapter 4 Basic Geometrical Ideas

These comprehensive RBSE Class 6 Maths Notes Chapter 4 Basic Geometrical Ideas will give a brief overview of all the concepts.

RBSE Class 6 Maths Chapter 4 Notes Basic Geometrical Ideas

→ A point has no length, breadth or height. A point is just a location marker. At point depicts the exact position of a object. It is generally denoted by a capital letter of English.

→ The smallest path joining two points shows therline segment. The line segment is shown by \(\overline{\mathrm{AB}}\) or \(\overline{\mathrm{BA}}\) joining A to B.

→ When we extend a line segment \(\overline{\mathrm{AB}}\) on both sides without any end points, we get a line that is again represented by \(\overleftrightarrow{\mathrm{AB}}\). Some time we denote it by l as well.

→ When two different fines meet or intersect at a point, these are called intersecting fines.

→ When two fines do not cut each other or intersect, these are called parallel lines.

→ Ray starts from a point and then goes to infinity in the same direction.

→ Any drawing (straight or non-straight) done without lifting the pencil may be called a curve. In this sense, a fine is also a curve.

→ A simple curve is one that does not cross itself.

→ A curve is said to be closed if its ends are joined; otherwise it is said to be open.

→ A polygon is a closed figure bounded by three or more line segments that intersect exactly to form a closed curve.

→ The line segments that forms a polygon is termed as sides. Any two sides with a common end point are adjacent sides. The meeting point of a pair of sides is called a vertex. The end points of the same side are adjacent vertces. The join of any two non-adjacent vertices is a diagonal.

→ Two rays drawn from a single common point makes an angle.

→ A three sided polygon is known as a triangle A triangle is denoted by the symbol A.

→ A quadrilateral is a four-sided polygon. (It should be named cyclically.). In any quadrilateral ABCD, \(\overline{\mathrm{AB}}\) & \(\overline{\mathrm{DC}}\) and \(\overline{\mathrm{AD}}\) & \(\overline{\mathrm{DC}}\) are pairs of opposite sides. ∠A & ∠C and ∠B & ∠D are pairs of opposite angles. ∠A is adjacent to ∠B & ∠D; similar relations exist for other three angles.

→ A circle is the path of a point moving at the same distance from a fixed point.

→ The fixed point is the centre, the fixed distance is the radius and the distance around the circle is the circumference.

→ A chord of a circle is a fine segment joining any two points on the circle.

→ A diameter is a chord passing through the centre of the circle.

→ A sector is the region in the interior of a circle enclosed by an arc on one side and a pair of radii on the other two sides.

→ A segment of a circle is a region in the interior of the circle enclosed by an arc and a chord.

→ The diameter of a circle divides it into two semi-circles:

→ Diameter of circle is double size of radius.