Highway engineers design on-ramps and off-ramps to be safe and efficient. The relation describing the maximum speed at which a car can safely travel around a flat curve without skidding is S= 2√(6.86R)+6 where S represents the maximum speed, in metres per second, and R represents the radius of the curve, in metres.
What is the radius of the curve where the maximum speed is 30 km/h? Round to the nearest tenth.