Police and private investigators often use the laws of mathematics to determine the circumstances behind incidents. One formula that is often used in car accident reconstruction is S is equal to the square root of 21d The formula says that S equals the square root of 21d. The variables are defined as follows: S= the car’s speed (in miles per hour) d= the length of the skid mark (in feet) Since police have the use of calculators in the real world, you are allowed to use a calculator in this lab to help you in determining the value of some radical expressions.
A police officer investigating an accident finds a skid mark of 115 ft in length. How fast was the car going when the driver applied the brakes? Round your answer to the nearest mile per hour.