You must have seen the objects you are of different shapes and sizes. You are always surrounded by shapes like triangles, squares and circles. Have you ever observed the shape of your house? They have length, breadth and height and so they are called as 3 dimensional or 3D shapes. Let us now learn more about them. Let’s do it right now.

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## What are 2D objects?

2 -D figures are nothing but the two-dimensional figures. A shape or a figure that has a length and a breadth only is a 2D shape. The sides are made of straight or curved lines. They can have any number of sides. Triangle and squares are the examples of 2D objects. We will classify figures we have seen in terms of what is known as the dimension.

A plane object that has a length and a breadth only have 2 Dimensions. They can be drawn on a screen or a paper. The following are the examples of 2D objects.

## 3D Shapes

3-D figures are nothing but the three-dimensional figures. In our day to day life, we see several objects like books, ball, ice-cream cone etc, around us which have different shapes. One thing common to most of these objects is that they all have some length, breadth and height or depth.

Therefore they all occupy space and have three dimensions. These objects cannot be drawn onscreen as it is a three-dimensional figure. The following are the examples of 3D objects.

## Nets for Building 3D Shapes

“A net is a two-dimensional representation of a three-dimensional figure that is unfolded along its edges so that each face the figure is shown in two dimensions. In other words, a net is a pattern made when the surface of a three-dimensional figure is laid out felt showing each face of the figure.” You have different nets for the different shape.

## Different Views of 3D Shapes

There are different views of 3D shapes such as top view and side view.

For example, the top view of a cylinder will be a circle but its side view will be a rectangle.

### Isometric Sketch

Isometric sketch of any shape is a 3D projection of that shape and all its lines are parallel to the major axis. Also, the lines are measurable. For example,

Three cubes each with 3 cm edge placed side by side to form a cuboid. Sketch an isometric sketch of this cuboid and find dimensions of the cuboid in cm.

Solution: Three cubes are side by side to form a cuboid. So, only one of the dimension change and the other two will remain the same. Two out of three dimensions of the cuboid will be 2 and the third will be 2 + 2 + 2 = 6. Thus, the dimensions of the cuboid are 2 × 2× 6

## Solved Examples for You

**Question 2: What cross-sections do you get when you cut a candle horizontally?**

- Rectangle
- Square
- Circle
- Triangle

**Answer :** C is the correct option. You get a circle when you cut a candle horizontally.

**Question 2: A bulb is burning just right above the ball. Name the shape of the shadow obtained.**

- Ball
- Hemisphere
- Ellipse
- Circle

**Answer :** A is the correct option. The shape of the shadow obtained will be of a ball.

**Question 3: What are 3d shapes examples?**

**Answer:** A cube, sphere, cone, rectangular prism, and cylinder are the basic 3-dimensional shapes that we observe around us. One can observe a cube in a Rubik’s cube as well as a die. Similarly, one can observe a rectangular prism in a box and a book. Also, a sphere can be observed in a globe while cone can be observed in a cone in a carrot.

**Question 4: Explain the definition of 3d shapes?**

**Answer:** 3D shapes refer to solid objects that consist of three dimensions. These dimensions are length, height, and width. 3D shapes objects happen to have depth to them.

**Question 5: Explain what is a 3d triangle?**

**Answer:** The tetrahedron refers to the three-dimensional case of the general concept of a Euclidean simplex. Furthermore, one may thus also call it as a 3-simplex. In the case of a tetrahedron, the base happens to be a triangle. Therefore, a tetrahedron is also called as a “triangular pyramid”.

**Question 6: Explain the face on a 3d shape?**

**Answer:** A face happens to be a 2D shape that is one surface of a 3D shape. Furthermore, an edge is where the meeting of two faces takes place.

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