 Hi and welcome to the session. Today we will learn about solid shapes. You must be aware of the shapes like a circle, a square, a rectangle, a quadrilateral, triangle, etc. These all are plane figures. We also come across many other shapes such as a cube or a cuboid, a cone that is an ice cream cone, pyramid, cylinder, sphere. A good example of a sphere is a ball. So such types of shapes are known as solid shapes. These solid shapes occupy some space and have three dimensions that is length, breadth and height or depth. So these are also known as three-dimensional shapes or 3D shapes. These plane figures are also known as two-dimensional shapes or 2D shapes because they have two dimensions. Now let's see the faces, edges and vertices of three-dimensional shapes. Consider a cuboid. The corners of a cuboid are its vertices. So this is a vertex of this cuboid. Now let us count how many vertices are there in a cuboid. So there are eight vertices in a cuboid. Now the rectangular surfaces of a cuboid are known as its faces. For example this is a face of this cuboid. Now let us count how many faces are there in a cuboid. There is one face at the top, one at the bottom, one in the front, one in the back and two on the side. So that means there are total six faces in a cuboid. Now the line segment where two adjacent faces meet is the edge of a cuboid. So here this is an edge of this cuboid. Now we will count how many edges are there in a cuboid. So we have one, then two, three, four, five, six, seven, eight, nine, ten, eleven and twelve. So there are twelve edges in a cuboid. In the same way you can find out the faces, edges and vertices of other three-dimensional shapes. Now our next topic is nets for building 3D shapes. To visualize 3D shapes on a paper we will learn how to form these 3D shapes with the help of nets of these shapes. For that first of all let us learn what is a net. A net is a skeleton outline of a solid that can be folded to make that solid. That means a net is a sort of skeleton outline in 2D which when folded results in a 3D shape. To understand the concept of a net in a better way consider this net. We will use this net to make a cube by folding it along its sides. So let's see how we do that. Now first of all we know that a cube has six faces which are all squares and here also in this net we have six squares. So let us number all these squares as one, two, three, four, five and six. Now first of all we will take the square numbered as three as the base for the cube. So here the square numbered as three is the base which will look like this. Now fold the square numbered as two along with this dotted line and the square numbered as four along with this dotted line. So square numbered as two will be at the back and square numbered as four will be in the front. And thus we will get a shape like this. So square numbered as two and square numbered as four will be opposite to each other. Now fold square numbered as one along with this dotted line and square numbered as five along with this dotted line. So square numbered as one will be on the left side of this shape and square numbered as five will be on the right side of the shape. So now square numbered as one and square numbered as five will be opposite to each other. So we will get the shape like this. Now lastly let us fold the square numbered as six along with this dotted line. So the square numbered as six will be on the top that is it will be opposite to the base which is square numbered as three. So from this we can see that square numbered as six and square numbered as three will be opposite to each other. And thus finally we get this shape which is a cube. So by folding this two dimensional net we have formed a three dimensional solid which is a cube. Now the same solid several types of nets that is to form a cube we can also have nets in some other shape. Thus in this session we have learnt about two dimensional shapes, three dimensional shapes, phases, edges and vertices of three dimensional shapes and nets for building three dimensional shapes. With this we finish this session hope you must have understood all the concepts. Goodbye, take care and have a nice day.