Considering the surface area of the spherical ballon, it will take 7 seconds for the the balloon to fully inflate.
The surface area of a sphere of radius r is given by:
[tex]S = 4\pi r^2[/tex]
In this problem, the surface area is of [tex]784\pi[/tex] cm², hence the radius in cm is found as follows:
[tex]784\pi = 4\pi r^2[/tex]
[tex]4r^2 = 784[/tex]
[tex]r^2 = \frac{784}{4}[/tex]
[tex]r^2 = 196[/tex]
[tex]r = \sqrt{196}[/tex]
r = 14 cm.
The radius start at 0 cm, inflating at a rate of 2 cm/s, hence it will take 7 seconds for the the balloon to fully inflate, as 14 cm/(2 cm/s) = 7 s.
More can be learned about the surface area of a sphere at https://brainly.com/question/21207980
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