Verify the identity of 1-sin a/cos a =cos a / 1+sin a

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

by definition, an arc subtended by a central angle of some given measure has the same measure. so .