What is a set of points in space equidistant from a given point called?

How many liters make 90 milliliters? Is it possible to have 3 legs? What expression represents the ratio of b to c? What is the meaningof equation? What is 13.5 as a mixed number? What are five consecutive numbers divisible by 4 and their summation is 100? How many years till the next millenuim? Formula for time? What is a 123 number? What is the area of a 15 sq foot square? What is a base area of 56 in and height of 6 in? Whats is the distance from -1 6 to 11 1? Is 4.121314 is a rational? What is a rational number that does not terminate? What are all the numbers that go into 81? A whole numbers consists of the digits 2468 and 0 if each digit is used only once how many whole number are possible? Is .35 greater than .3? How do you round to the nearest cent 2448.97? What is larger 0.04 or 0.018? What is 3 divided by 1956?