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 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.