Decide whether or not each equation represents a proportional relationship. a. Volume measured in cups ( ) vs. the same volume measured in ounces ( ): b. Area of a square ( ) vs. the side length of the square ( ): c. Perimeter of an equilateral triangle ( ) vs. the side length of the triangle ( ): d. Length ( ) vs. width ( ) for a rectangle whose area is 60 square units: