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

1 inch ≈ 1.578 × 10^ -5 miles.

In scientific notation, to obtain the original whole number. Move the decimal to the left if the exponent is negative and to the right if the exponent is positive.
So 1 inch = .00001578 miles
1225 / .00001578 = 77629911.28

To obtain the answer in scientific notation, move the decimal to the left until you have a single digit whole number and the rest of teh digits are to the right of the decimal. In this case 7 places. Now show it multiplied by 10 to an exponent equal to the number of places you moved the decimal. In this case the 7th exponent.

7.763 x 10^7