The diagonals of a rhombus measure 18 feet and 12 feet. What is the perimeter of the rhombus? Express your answer in simplest radical form.

The diagonals of a rhombus bisect each other.......this bisection forms a right triangle with each leg (1/2) the length of its respective diagonal.....the hypotenuse forms one of the equal sides

So.....the perimeter is given by  

4√ [ 9^2 + 6^2  ] =

4 √117  =

4 √ (9 * 13 )  =

12√13 ft