Question

The surface area of a sphere is 16 square units. The radius of the sphere measures

Answer 1

For this case we have that by definition, the surface area of a sphere is given by:

$SA = 4 * \pi * r ^ 2$

They tell us as data that the surface area of the sphere is 16 \ units ^ 2.

$16 = 4 * \pi * r ^ 2$

We cleared the radio:

$\frac {16} {4} = \pi * r ^ 2\\4 = \pi * r ^ 2\\\frac {4} {\pi} = r ^ 2\\1,27388535032 = r ^ 2\\r = \pm \sqrt {1,27388535032}$

We take the positive value, rounding:

$r = 1.13 \ units$

Answer:

$r = 1.13 \ units$