A rhombus has sides of length 51 units each and a shorter diagonal of length 46 units. What is the length, in units, of the longer diagonal?
1/2 the length of the other diagonal =
sqrt [ 51^2 - ( 46/2)^2 ] = sqrt [ 51^2 - 23^2 ] = sqrt (2072) = 2 sqrt (518)
The longer diagonal = 2 * [ 2 sqrt (518) ] = 4sqrt (518) ≈ 91 units (rounded)