18 + FG =20
FG = 20-18
FG = 2
Add 5 to both sides of the equation.
Divide both sides by 6 to get x alone.
As long as you multiply or divide both sides of the ratio by the same number, you will have an equivalent ratio.
The inside angles of a 4 sided shape when added together equal 360.
X = 360 - 50-130-120
X = 60 degrees.