Question

The total amount of fresh water on earth is estimated to be 3.73 x 10^8 km^3. What is this volume in cubic meters? in cubic feet?

Answer 1

The total amount of fresh water on earth is $3.73 *10^{8} km^3$

 Hence the volume of water $v= 3.73*10^{8} km^{3}$

we are asked to convert this into cubic metre and cubic feet.

we know that 1 km = 1000 m.

                     $1 km^3 = [10^3 m]^3$

                     $1 km^3 = 10^{9} m^{3}$

       we have been given  $v = 3.73 *10^{8} km^3$

                                            $v = 3.73 *10^{8} *10^{9} m^{3}$      

                                              $v = 3.73*10^{17} m^{3}$  [ANS]

Now we have to  convert it into cubic feet

we know that one metre =  3.28083 feet

                   $1 m^{3} =[3.28083feet]^{3}$

                    $1 m^{3} =35.3143472 feet^{3}$

         Hence  $v =3.73*10^{17} m^{3}$

                       $= 3.73*10^{17} *35.3143472 feet^{3}$

                  ⇒  $v = 131.7225*10^{17} feet^{3}$  [ANS]

Answer 2

One km^3 is 1,000,000,000 m^3=10^9 m^3 hence 3.73 10^8 km^3 is 3.73 10^17 m^3

One meter is 3.28084 feet hence 1 m^3 is (3.28084)^3 feet

Thus 3.73 10^8 km^3 is 3.73*35.315 10^17 = 132 cubic feet