Does anybody know how to do this math problem?!?

Question

the questions asks...

1)A globe has a diameter of 12 in. how much paper dies it take to make the map? heres another...

2) how much air will a balloon with a radius of 2 ft hold?

Answer 1

1)

     Diameter of the globe is 12 inches

     Since diameter is equal to two times of the radius

     So, diameter = 2 × radius

               d = 2r

              d² = 4 r²

              r² = d²/4

    Surface area of the sphere is  4 × pi × r²

                                                =    4 × (3.14) × d²/4

                                                =    4 × (3.14) × (12)²/4

                                                =    4 × (3.14) × 144/4

                                                =    3.14 × 144

                                                =    452.16 inches

    So, the quantity of paper to make the map is   452.16 inches

Answer 2

2)

    Radius of the balloon is r = 2 ft.

    Since balloon has sphere like structure

    Volume of the sphere is    4/3 × pi × r³

                                         =  4/3 × (3.14) × (2)³

                                 =  4/3 × (3.14) × 8

                                         =  33.493 ft

                                         =  0.94841 cubic meters

     The balloon will hold 0.94841 cubic meters of air