Hey! I don’t know if this is what you mean.. but I tried to understand it.
78^1
73^1
Have a good day :)
Answer:
cos 60° = one half because the angles are complements
Step-by-step explanation:
He would have 21 before he bought the 10 stamp because 31-10=21
1. 
2. 
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4. (1st option) Yes; the number is written in scientific notation.