The surface area of a sphere is given by A = 4 space pi r squared, where r is the sphere's radius. If a sphere's surface area grows at a rate of 16 cm2 per second, at what rate is the radius of the sphere increasing (in cm per second) at the instant the sphere has a radius of 4 cm?

5   1/4   miles per hour

step-by-step explanation:

15   3/4 / 3 = 5   1/4

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b