what is the height of the missing rectangle of the histogram
Each of the rectangles in the histogram has a base of 25, and the heights are 3, 7, 8, 10, 1, and 1. Thus the total area of the histogram is 3x25+7x25+8x25+10x25+1x25+1x25=750. We want the value with area 750/2=375 to the right of it and 375 to the left of it.