An architect is designing a new windmill with four sails. In his sketch, the​ sails' center of rotation is the​ origin, (0,0), and the tip of one of the​ sails, point Upper R, has coordinates (2,-4).
He wants to make another sketch that shows the windmill after the sails have rotated 180 degrees about their center of rotation. What would be the coordinates of Upper R prime ?
The coordinates of Upper R prime would be ?