Answer:
Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the 10. If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.
7.75 × 10^−3
So Serena is 10, and her mother is 3 times ten, so her mother is 30. And if we take 30 minus 10 we will have the age of the mom when Serena was born, which is 20. So we know that when Serena is 20, her mother will be 40. So when Serena is 20, she will be half of her mother's age. 40 × 0.5 = 20.
Answer:
I think its 8a because in a regular octagon we have 8 sides.
