The lengths of the diagonals of a rhombus are 18 cm and 24 cm. what is its perimeter and what is the distance between the parallel sides?

D1 & d2 are the diagonal lengths 
-side of a rhombus, if diagonals are given, can be calculated by 
s = sqrt(d1^2 + d2^2) 
  this is just pythagorean theorem 

side  = sqrt(24^2 + 18^2) 
side = sqrt(900) 
side = 30 cm 

perimeter = 4*s 
perimeter = 4*30 
perimeter = 120 cm
thats all  i can with, idk about the distance part

Yes, that is the correct formula. to solve this problem given the number of years, plug in the number of years for t and plug the whole thing into the