Answer:
3x m
Step-by-step explanation:
Area of Rhombus = Diagonal 1 * Diagonal 2
(3x² + 6x) = (x + 2) * Diagonal 2
3x(x+2) = (x + 2) * Diagonal 2
3x(x+2)/(x + 2) = Diagonal 2
3x = Diagonal 2
L of Diagonal 2 = 3x m