Using proportions, it is found that the Customer Acquisition Cost was of $1,215.
A proportion is a fraction of a total amount.
In this problem, the customer acquisition cost is the spending in sales divided by the number of customers added.
80 customers were added, considering costs of 1200 + 9000 + 87000 = $97,200, hence:
97200/80 = $1,215.
More can be learned about proportions at https://brainly.com/question/24372153