As marta built a square fence around her garden, she wondered how much she would have to pay if she increased the length of each side of the fence by the same number of meters. each meter of fence costs 3 dollars. which of the following functions best describes the additional amount of money marta will have to spend, in dollars, if she increases each side of the fence by m meters?

Given that as Marta built a square fence around her garden, she wondered how much she would have to pay if she increased the length of each side of the fence by the same number of meters.

Suppose the she increases each side of the fence by m meters, then the total increase to the four sides of the square is given by 4m.

Given that each meter of fence costs 3 dollars, therefore, the function that best describes the additional amount of money Marta will have to spend, in dollars, if she increases each side of the fence by m meters is given by C = 12m.