Page 1 - Lesson Notes-Ch.13 SA and Volumes(Cuboids and Cubes)
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SAI International School
                                                     CLASS - IX

               Mathematics
               CHAPTER-13: SURFACE AREAS AND VOLUMES

               Lesson Notes-1
                   SURFACE AREA AND VOLUME OF CUBOIDS AND CUBES

                   INTRODUCTION:

                   Plane figures


                   The figures which we can draw on a piece of paper or which lie on a
                   plane are called Plane figures.

                   Example - Circle, Square, Rectangle etc.


                   Solid figures


                   The 3D shapes which occupy some space are called Solid figures or
                   Solids.

                   Example - Cube, Cuboid, Sphere, Cone etc.


                   Surface Area


                   The sum of  the area of all the faces of the solid shape is the total
                   surface area of that figure. The unit of surface area is a ‘square’ unit.


                   VOLUME:


                   Space occupied by any solid shape is the capacity or volume of
                   that figure. The unit of volume is a ‘cubic’ unit.


                   If an object is solid, then the space occupied by such an object is
                   measured and is term as the Volume of the object. On the other
                   hand, if the object is hollow, then interior is empty, and can be
                   filled with air, or some liquid that will take the shape of the
                   container. In this case,the volume of the substance that can fill
                   the interior is called the capacity of the container .


                   In general, the volume of an object is the measure of the space it


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