The set consisting of only common element element of two sets is called the two sets

Each object in a set is called an element of the set. two sets are equal if they have exactly the same elements in them. a set that contains no elements is called a null set of empty set. if every element in set a is also in set b then set a is a subset of set b. hope this : )

The answer is: a = about 63.59ft2 for 15