Can someone help me on this question

Asequence is a function whose is the set of natural numbers

True or false: dilations map angles of the same degrees

The length of a rectangular board is 3 feet less than twice its width. a second rectangular board is such that each of its dimensions is the reciprocal of the corresponding dimensions of the first rectangular board. if the perimeter of the second board is one-fifth the perimeter of the first, what is the perimeter of the first rectangular board?