 # Introduction to solid shapes

Many objects in our day to day lives like book, pencil box, ice cream cone, football and cylinder are three-dimensional objects. All these objects occupy some shape and space. Also, they have three dimensions- length, breadth and height or depth. For example, a figure drawn on paper which has length, breadth and height is called 3-d figure. Mathematically,  3D shape has three dimensions. The D in 3D stands for dimensional. In a world with dimensions, we can travel forward, backward, right, left, and even up and down.

Some of the solid shapes in geometry are cube, cuboid, cone, cylinder, pyramid, prism, and so on. We can see many objects in real-life which look exactly like them in terms of shape. For example, bowls are in the shape of a hemisphere, balls, globe are in the shape of a sphere, dice are in the shape of a cube, match box, refrigerator, bricks are in the shape of a cuboid, and so on.

In many cases we are using the formulas of three-dimensional shapes in day-to-day life in order to accomplish some of the other tasks. For example, in order to wrap a hemisphere-shaped object with wrapping paper or in order to figure out how much wrapping paper is required it is necessary to calculate the surface area of a hemisphere.

Similarly, when we place a spherical object into a container filled with water, then the amount of water that overflows is equal to the volume of that object. Archimedes principle practically gives you the volume, but using this principle is not possible every time. For finding the formula for the volume of sphere, we insert the spherical body in a cylindrical container. Consider the radius of the circular bases of the cylinder is equal to the radius of the spherical body also, the spherical object touches the top and bottom of the container and its diameter is equal to the height of the container. Now the volume of a spherical object will be 2/3 of the cylindrical container.