Answer:
C
Step-by-step explanation:
The diagonals of a rectangle are congruent, then
5x - 31 = 2x + 11 ( subtract 2x from both sides )
3x - 31 = 11 ( add 31 to both sides )
3x = 42 ( divide both sides by 3 )
x = 14
Then
RT = 2x + 11 = 2(14) + 11 = 28 + 11 = 39
The diagonals are each 39 units
