Answer:
4.73 x 10^9
Step-by-step explanation:
(8.6 x 10^4) (5.5 x 10^4
= 8.6 x 5.5 = 47.3 and 10^4 x 10^4 = 10^8
= 4.73 x 10 x 10^8
= 4.73 x 10^9
