Answer:
12 units
Step-by-step explanation:
Properties of Rhombus:
1. length of all sides are equal.
2. Diagonals bisect each other at right angles
As the length of all sides are equal,
JM = JK
3x = 2x + 4
Subtract 2x from both sides,
3x - 2x = 4
x = 4
JM = 3*4 = 12 units
