Answer:
x=26
Step-by-step explanation:
fdg is a 90 degree angle. 3x+12 3x26=78 78 plus 12 equals 90
If EFGH is a rhombus, then the diagonals are perpendicular. Therefore m∠FDG = 90°.
Therefore we have the equation:
3x + 12 = 90 subtract 12 from both sides
3x = 78 divide both sides by 3
