12.2.1 Symmetry (continued)
Example 3 Biology Application
Whether a diatom, an aquatic single-celled organism with a cell wall made of silica, has symmetry and the nature of any symmetry are determined in this example. This diatom does not have line symmetry. It does have rotational symmetry, with an angle of rotational symmetry of 180° and an order of 2.
Whether a diatom has symmetry, and the nature of any symmetry, are determined in this example. This diatom does have line symmetry. There are four lines of symmetry. It also has rotational symmetry, with an angle of rotational symmetry of 90° and an order of 4.
Example 4 Identify Symmetry in Three Dimensions
Whether a three-dimensional figure has symmetry, and the nature of any symmetry, are determined in this example. This pentagonal prism has six plane symmetries. It also has symmetry about six axes.
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