The weight in grams of a handlebar with a radius of x millimeters can be modeled by the function f(x)=1001.05x . When x = 15, the instantaneous rate of change is 10.14. What does this mean? It means that when the radius of a handlebar is 15 millimeters, its weight is 10.14 grams per millimeter. It means that the radius is increasing by 10.14 millimeters. It means that the handlebar's radius is 15 millimeters when the weight is 10.14 grams. It means that when the radius of a handlebar is 15 millimeters, its weight is increasing by 10.14 grams per millimeter