Question

Use scientific notation to estimate the number of inches in 1,225 miles

Answer 1

First, find the number of inches
1225 Miles = 77616000 Inches

then, move the decimal to until you have a ones place.   
77616000.    the decimal for this number moves to the left SEVEN places.
you end up with 7.7616000

it will look like this:

7.8 * 10^7

I rounded to the .8 because you didn't state how many significant figures, but it could easily be 7.76 * 10^7

the exponent above the 10 will tell you how many places to move. to get back to your original number, move it back to the right seven places. Of course, you would have to place hold the numbers with 0s. If it were negative, you would move the decimal the opposite way.