Answer:
d. 5.454 x 10^7 square kilometers
Step-by-step explanation:
Adding 4.46×10^7 to 0.994×10^7 we get 5.454×10^7.
___
Before you can add numbers in scientific notation, they must both have the same multiplier. Here, we can see that the area of Asia will be written with an exponent of 7, so we choose to write both numbers that way.
44,600,000 = 4.4×10,000,000 = 4.4×10^7
9.94×10^6 = (0.994×10)×10^6 = 0.994×10^7
The sum is (4.400 +0.994)×10^7 = 5.454×10^7.