Answer:
4.2 x 10^9
1 x 10^9
7.4 x 10^8
6 X 10^8
3.7 X 10^7
Step-by-step explanation:
The higher the exponent the bigger it is, so arrange by powers first
1 x 10^9
4.2 x 10^9
7.4 x 10^8
6 X 10^8
3.7 X 10^7
Now put the numbers in order from biggest to smallest within exponent powers
4.2 is greater than 1 and 7.4 is greater than 6
4.2 x 10^9
1 x 10^9
7.4 x 10^8
6 X 10^8
3.7 X 10^7