Two solids are similar if one is an enlargement, a reduction or a reproduction of the other.
Properties
- All cubes are similar solids.
- All spheres are similar solids.
- The corresponding lengths in similar solids are proportional.
Example
The dimensions of prism A are : a, b and c.
The dimensions of a similar prism B are : ka, kb and kc.
The ratio of similarity is k :
- If \(k=1\), then the two solids are congruent; one is a reproduction of the other.
- If \(0< k< 1\), then prism B is a reduction of prism A;
- If \(k> 1\), then prism B is an enlargement of prism A.
The volume of solid B is equal to the volume of solid A multiplied by the cube of the ratio of similarity k.
The area of solid B is equal to the area of solid A multiplied by the square of the ratio of similarity k.