What do parabolas represent?

Answer 1

Parabolas represent quadratic relationships, rather than linear relationships, which are demonstrated by a straight line, A quadratic relationship is modeled by a curve, known as a parabola.

Examples of information parabolas are used to graph would be the effect of a price increase on revenue. If the price increases and sales decrease steadily, the revenue will at first increase because the of the extra money made selling each product. Eventually, the price will become too high and sales will become so low the the revenue will slowly decrease. This relationship can be modeled by a curve that slowly rises, peaks, then slowly sinks down. It is symmetrical and quadratic. The optimal value, or maximum revenue in this case, is the vertex of the parabola (the highest point it reaches).