All Your Vsualising Solid Shapes Class 7 Notes
When you look around your room or your classroom or any place you go, it is filled with different shapes. Right from the rectangular book which you read last till your glass of milk in the form of a cylinder, shapes are all around us. This is the reason why visualising solid shapes is one of the most important skillsets every one should learn.
It is necessary to teach distinguishing between different shapes and sizes. The healthy collection of tips and notes regarding visualising solid shapes class 8 will help you in your upcoming exams.
Two Dimensional Shapes
For introduction of visualising solid shapes, we will first learn about 2D shapes. Shapes which we can draw on paper or other flat surfaces are called two-dimensional shapes or plane figures. We cannot touch or feel 2D shapes as we can for 3D shapes, which we will learn about later. 2D shapes only have length and width.
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Three Dimensional Shapes
Another vital topic for visualising solid shapes class 8 notes is the concept of 3D shapes, also known as solid figures. Solid figures are usually defined by three dimensions – length, height and width. These figures can be felt by human touch and cannot be drawn on flat surfaces.
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Vertices, Edges and Faces of 3D Figures
In 3D or solid figures for visualisation of solid shapes, faces are the flat 2D surfaces (of any shape) which are joined with lines and points to make solid figures.
Similarly, edges are those line segments at which the faces of solid figures meet.
In contrast, vertices are the points where two or more edges meet.
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Here is a table which will help you in your NCERT solutions for class 8th maths chapter 10 visualising solid shapes.
Did You Know?
Euler’s Formula states that the no. of faces, edges and vertices in a regular shape are related via the formula F + V = E + 2.
Pop Quiz 1
How many faces does a sphere contain?
0
1 (Answer)
Infinite
10
Geometric Nets for 3D Shapes
A very important concept for class 8 visualising solid shapes and class 7 visualising solid shapes is that of geometric nets. Geometric nets are 2D figures which are obtained when a 3D figure is opened up. The net can then be folded back to reconstruct the original 3D figure. For example, take a look at the below figure.
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How to Draw 3D Figures on Flat Surfaces?
There are two ways to draw solid figures on flat surfaces. The process is generally called visual illusion and is required for visualising solid shapes class 8 NCERT solutions and visualising solid shapes class 7 NCERT solutions.
Oblique Sketching
In oblique sketches, even though it seems we have drawn the whole figure, we cannot get the complete view of the figure and the length of all the edges are also not the same. This is a popular area for teachers to ask questions from in NCERT solution of class 7 of maths chapter visualising solid shapes.
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Isometric Sketching
Special sheets called isometric sheets are available upon which dots are constructed to make several equilateral triangles. You can draw 3D figures on such sheets such that the original dimensions of the figure are proportional to the sizes we draw. This process is called isometric sketching and is an important concept for class 8 maths visualising solid shapes.
So, this was all regarding visualising solid shapes, and covers enough for NCERT class 7 maths visualising solid shapes and NCERT class 8 maths visualising solid shapes. To know more about this topic and or any other questions on visualising solid shapes, visit the Vedantu website or download our mobile app today!
FAQs on Visualising Solid Shapes
1. What are Plane Figures or 2D Figures?
Ans. An area where many visualising solid shapes class 7 extra questions are asked from is 2D shapes and figures. Shapes which we can draw on paper or other flat surfaces are called two-dimensional shapes or plane figures.
We cannot touch or feel 2D shapes in contrast to 3D shapes, which we will learn about later. 2D shapes only have length and width. Squares, rectangles, triangles, circles, straight lines, parallelograms and hexagons are the most popular of all plane figures.
2. What are Solid Figures or 3D Figures? What are the Most Popular Solid Figures?
Ans. Another area from where many visualising solid shapes class 8 extra questions are asked is 3D shapes or solid figures. Solid figures are usually defined by three dimensions – length, height and width.
These figures can be felt by human touch. We have a special technique known as visual illusion through which we can portray solid figures on flat surfaces, but that is also not error-free. 3D shapes have faces, edges and vertices which are not present in 2D figures. There are primarily two ways to draw solid figures on flat surfaces.
3. What do you Mean by a Sphere?
Ans. The definition of a sphere is a popular question in NCERT solutions for class 8 maths chapter visualising solid shapes. If we take any point in a three-dimensional space, all the points which are at a particular distance, say r, from the initial point, is called a sphere. The initial point taken is called the centre of the sphere, while the fixed distance r is called the radius of the sphere. All the points which are at r distance from the centre make up the surface of the sphere.
4. What are the two Types of Visual Illusion with Which we can Draw 3D Figures on 2D Surfaces?
Ans. In NCERT solutions for class 7 maths visualising solid shapes, visual illusion is an important topic. There are two types of visual illusion – oblique sketching and isometric sketching. In oblique sketches, even though we have drawn the whole figure, we cannot get the whole view of the figure and the length of all the edges are also not the same.
On the other hand, in isometric sketching, isometric sheets are available upon which dots are constructed to make equilateral triangles. 3D figures are drawn on such sheets such that the original dimensions of the figure are proportional to the drawn sizes.
