To determine which statement is true, let's analyze them based on trigonometric identities.
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sin 90° = 1 - This is correct, as given.
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cos 0° = 1, because the angles are complements - This is true. The complement of 0° is 90°, and cos 0° = 1.
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cos 90° = 1, because the angles are supplements - This is false. The supplement of 90° is 90° itself, and cos 90° = 0.
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cos 0° = 0, because the angles are complements - This is false. We already established that cos 0° = 1.
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cos 90° = 0, because the angles are supplements - This is true, as cos 90° indeed equals 0, but the reasoning regarding supplements is irrelevant here.
Based on this analysis, the following statements are true:
- cos 0° = 1, because the angles are complements.
- cos 90° = 0.
The most correct statement, fitting the criteria asked in your question, is:
cos 0° = 1, because the angles are complements.