**Important Concepts and Formulas**

1. The shapes such as cubes, cuboids,
cylinders, cones and pyramids are called solid shapes or three-dimensional shapes.

2. The flat surfaces of a solid shape
are called the faces and the corners are called the vertices.

5. There are two different types of
sketches that are possible for a solid shape. They are oblique sketch and
isometric sketch.

6. An oblique sketch conveys all
important aspects of the appearance of a 3D shape, though it does not have
proportional lengths of its edges.

7. In an isometric sketch of a 3D shape,
the measurements are kept proportional.

8. We can view a solid shape in
different ways. A solid shape looks different if we view it from different
angles.