Annette bought 3 notebooks for $0.80 each and a pack of pens for $1.20. She gave the clerk some money and got back $1.40 in change. How much money did Annette give the clerk

3(.80)+1.20= 3.60

3.60+1.40= 5

Annette gave the clerk $5

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since the cosine is the ratio of the adjacent side to the hypotenuse, you can see that cos 60° = ½. answer. according to the property of cofunctions (topic 3), sin 30° is equal to cos 60°. sin 30° = ½.