A large balloon in the shape of a sphere is being filled with helium. The balloon has a radius of 1 foot. Helium costs $0.80 per cubic foot. What is the cost of filling the balloon with helium?

$3.35

Step-by-step explanation:

volume of balloon in the shape of sphere= 4/3 * pi * r^3 = 4.189 cubic foot

cost of 1 cubic foot of helium = 0.8

cost of 1 * 4.189 cubic foot of helium = 0.8 * 4.189 = 3.35

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