Calculate the Earth's Volume in Km^3 and Scientific Notation ?

Earth's volume
= (4/3) × π × r³
= (4/3) × 3.141592 × 6371³ km³
= 1.083 × 10¹² km³ (to 4 sig. fig.)

Sorry, my answer is "Anonymous" as your post is Anonymous. There is no need for an Anonymous question in this category, Most 'Anonymous' posts are trolls, maybe yours is not, but the high likelihood is there. If you post as yourself, I would be glad to help you with any problem you have.
I spend a lot of time on each problem, I just want to make sure it's for a worthwhile cause.

V=4(3.14159)(6371^3)/3~1.083206691*10^12 km^3.

 The Earth's Volume in Km^3 and Scientific Notation:
 r = Average radius of Earth = 6371 km
 π = 3.141592
 V = 4/3 × π × r^3

 V = 4/3 × 3.141592 × 6371^3 km^3
   = 1.083206691490953482666... × 10^12 km^3

 1 km^3 = 1 × 10^15 cm^3

 m = Mass of Earth = 5.98 × 10^27 g

  

5.98 x 1027 g ?? totally wrong
      value is 5.974e24 kg ... but don't need that
1 km^3 = 1 x 1015 cm^3 ?? totally wrong      
1 km³ = 1e9 m³

kg and m are the proper SI units

R = 6371 km = 6.37e6 m
Sphere V = ⁴/₃πr³

V = ⁴/₃π(6.37e6)³ = 1.083e21 m³
1.083e21 m³ x (1 m/1000 km)³ = 1.083e12 km³

(published value Volume 1.083e12 km³)

V = (4/3)πr³
V = (4/3)(3.141592)(6371 km)³
V = 1.083 x 10¹² km³