At Nolan's Car Rentals, customers will pay $60 to rent a mid-sized car for the first day, plus $5 for each additional day. At Westford Rent-a-Car, the price for a mid-sized car is $50 for the first day and $10 for every additional day beyond that. Find the solution to the system.

Imagine that we cut the cone in half with a vertical plane. In this plane we'd see points a, b and c. We need to find the measure of angle bca, and then double that angle, to obtain the answer to this problem.

Note that tan (angle bca) = opp / adj = 2 / 6, or 1/3, or 0.333...

Working backwards to find angle bca, we use the inverse tangent function:

arctan 0.3333.. = approx. 0.322 radians, or 18.435 degrees.

Doubling that gives us the measurement of the angle formed between the line segments: 2(18.435 deg) = 36.9 degrees, approximately.