# Basic Geometrical Ideas

## A Short Overview of Basic Geometrical Ideas Class 6

Geometry is the branch of mathematics that deals with sizes, shapes and dimensions of figures, angles, lines, surfaces, etc. The word originated from Greek word “Geometron” where “Geo” and “metria” means earth and measurement respectively. Students should have a thorough knowledge of Basic Geometrical ideas which will help them to quickly grasp more advanced concepts that they will come across in future classes.

Additionally, learning about basic geometrical concepts will also enable them to develop critical skills such as problem-solving skills, spatial reasoning, deductive and analytical reasoning. It will also come in handy while solving other mathematical concepts.

Basic Geometrical Concepts Class 6

Learning Basic geometrical concepts is essential not only from an academic point of view, but it also has several practical applications. It is required in various fields such as architecture, astronomy, engineering, video games, art forms, cloth and food designing and so on. Thus, students must have a grasp of the basic geometrical ideas.

The basic terms and geometric ideas have been discussed below.

Basic Geometry for Class 6 – Point -

It is one of the most basic geometrical ideas for class 6. A point can be described as a dot on the paper. In geography, a point which has no length, width or height is used to specify a location. As such, it is usually denoted by a single capital letter. For instance, two points on a paper can be named as Point A and Point C.

Fig 1.1

Basic Geometric Ideas 6th Grade - Line segment -

A line segment is another one of basic geometrical ideas. It can be defined as the shortest route between any two points. For instance, a line connecting two points A and B can be denoted as  $\overline{AB}$.

The points A and B are known as the endpoints. You can go through basic geometrical ideas, class 6 questions and answers to learn how to draw a line segment.

A Line segment can also have a midpoint which separates it into two equal parts. Thus, if C is the midpoint of the line segment $\overline{AB}$, then AC = CB.

Additionally, as you solve questions on basic geometrical ideas for class 6, you will understand how line segment can also be a part of a line which is infinite.

Basic Geometrical Ideas of Class 6 – Lines -

A line which is one of the most basic geometrical concepts after point, is a straight one-dimensional geometrical shape that extends infinitely in both directions.

Apart from length, a line does not have any width or height. It can pass through numerous points; hence it is named by picking any two points on it. For instance, a line passing through points P and Q can be denoted as $\overset{\leftrightarrow }{PQ}$. Alternatively, it can also be denoted by a single alphabet such as p, q.

According to basic geometric ideas, Lines are categorised into -

• Intersecting lines - When two lines or line segment cross or intersect each other at a common point, it is known as intersecting lines.

• Parallel line – Pair of lines that never meet each other at any point is known as parallel lines. They can be denoted as $\overset{\leftrightarrow }{AB}$ II $\overset{\leftrightarrow }{PQ}$ .

Fig 1.3

Class 6 Chapter 4 Basic Geometrical Ideas – Curves -

In class 6 maths basic geometrical ideas, students will also learn about curves. Figures that are not wholly straight are referred to as curves.

One can go through NCERT Solutions for class 6 maths chapter 4 basic geometrical ideas to learn about these different types of curves and how to draw each one of them.

Basic concepts in geometry Class 6 – Polygons -

A simple geometrical figure that is enclosed with line segments on all sides is known as a polygon. These line segments are called sides, and the meeting point of two sides is referred to as its vertex. Consider, for example, a polygon with four sides $\overline{AB}$, $\overline{BC}$, $\overline{CD}$, $\overline{DE}$.  Now the sides $\overline{BC}$, $\overline{CD}$ meet at common point C, which is a vertex of polygon ABCDE. Additionally, the sides of a polygonal are non collinear.

Fig 1.6

6th Class Basic Geometrical Ideas – Angles: -

When two rays emerge from a common endpoint, it forms a corner or angle. The rays are referred to as the sides, whereas the endpoints are considered the vertex of an angle. If the two sides of a corner are AB and BC, then it can be named as ∠ABC.

You can solve the questions from basic geometrical ideas class 6 exercise 4.3 to learn how to name angles correctly.

Students should keep in mind that while specifying and naming an angle, the vertex should always be in the middle. There are different types of angles called acute angle, right angle, obtuse and straight angle. After you attempt the questions from the exercise, you can refer to NCERT solutions for class 6 maths chapter 4 exercise 4.3.

Basic Geometry Ideas Class 6 – Triangles -

A three-sided polygon is called a triangle, which is a part of basic geometrical concepts. Along with three sides, it also has three vertices and three angles. In geometry, a triangle is written as ABC. It also has an interior and exterior.

Go through the basic geometrical ideas class 6 extra questions under this topic for a better conceptual understanding of triangles.

Basic Geometric Shapes Class 6 – Quadrilaterals -

According to basic geometrical ideas, a polygon with four sides is known as a quadrilateral. Additionally, it also has four angles and vertices. One will come across various forms of four-sided quadrilaterals such as squares, rectangles, trapezoids, rhombuses etc.

After you solve the questions under this topic for yourself, you can refer to NCERT solutions class 6 maths chapter 4 exercise 4.5 to check your knowledge of the concepts.

Fig 1.9

Basic Concepts in Geometry Std 6 – Circles -

Circles form another vital part of basic geometrical ideas. It is a geometric figure which has no start point and endpoint. The line segment that connects the centre of a circle to any point on it is defined as a radius.

Additionally, a line segment whose endpoints lie on the circle and which passes through the centre is called its diameter. It also divides the circle into two equal parts. Practising the questions on basic geometrical ideas for class 6 will help you to learn how to draw diameters.

Besides diameter, a line segment that connects two points on a circle is known as chord whereas an arc can be defined as a portion of a circle. You can refer to NCERT solutions for Class 6 maths basic geometric ideas to know more on arcs and chords.

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1. Which are diagonals, adjacent sides, and vertices of a polygon?

Ans. In CBSE class 6 maths basic geometrical ideas, adjacent sides have been defined as two sides of a polygonal which have the same endpoints. Moreover, adjacent vertices are the endpoints of the same side.

A line segment that connects two non-adjacent vertices of a polygon is known as a diagonal. Answering the questions from basic geometrical ideas exercise 4.2 will help you to have a clearer understanding of various other aspects of a polygonal.

You can refer to our solutions for NCERT class 6 basic geometrical ideas to learn more about a polygonal.

2. What are the various types of triangles?

Ans – Types of triangles are -

• Equilateral triangle – It is a triangle which have three sides of equal length and each angle is of 60°.

• Right-angled triangle – A triangle whose one angle measures 90° and other two angles are less than 90° is called a right-angled triangle.

• Isosceles triangle – A triangle that has two sides of equal lengths are called Isosceles triangle.

• Scalene triangle – Any triangle that has three sides of three different lengths can be called scalene.

• Acute triangle – An acute triangle is a triangle with three acute angles (less than 90 degrees).

• Obtuse triangle – It is a triangle with two acute angles and one obtuse angle (greater than 90 degrees).

3. What are the different types of curves?

Ans – A curve which is an integral part of basic geometrical ideas can be categorised into several types –

• Simple curve - It is a type of curve which do not intersect itself at any point. One of the critical basic geometrical concepts, students should keep in mind is that simple curves can be both open and closed.

• Non-simple curve - A curve that intersects itself.

• Closed curve - A curve that has no endpoints and has enclosed an area.

• Open curve - A curve that has two definite endpoints.

• Upward curve - Curves that move at an upward direction.

• Downward curve - Curves that move in a downward direction.