Find the area of circle with radius D cm

In the 30-60-90 triangle below side s has a length of and side r has a length

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10