FQ is defined as a quarter yard cut "fat". IOW - you cut one HALF yard by the WOF then cut the WOF in half making a quarter yard total square inches.
So ... given that a YARD is defined as 36" ... a FQ is ALWAYS at least 18" X (1/2 the WOF). The 1/2 the WOF can vary from bolt to bolt but is generally 44" so *most* FQ's are 18" X 22".