Aspherical balloon has a circumference of 21 cm. what is the approximate surface area of the balloon to the nearest square centimeter? a. 1,385 cm^2 b. 561 cm^2 c. 346 cm^2 d. 140 cm^2

Surface area of sphere = 144 cm².

Step-by-step explanation:

Given  : A  spherical balloon has a circumference of 21 cm.

To find :  What is the approximate surface area of the balloon to the nearest square centimeter,

Solution : We have given that circumference of sphere = 21 cm.

Circumference of sphere = 2 * pi * radius .

Plug the value of circumfrence

2 * pi * radius  = 21 cm

2 * 3.14 * radius = 21

radius * 6.28 = 21

On dividing by 6.28 both sides

Radius =  

Radius =  3.34 cm

Surface area of sphere = 4 * pi * (radius )².

Surface area of sphere = 4 * 3.14 * (3.34 )².

Surface area of sphere = 144.11 cm²

Therefore, Surface area of sphere = 144 cm².

(a) the volume of the cone is 20/3 in3

hence, option a is correct.