rectangle area = length * width
2100 = 50 * w
width = 2100/50 = 42 feet
the three rectangles suppose there widths are as :x ft,3x ft , 2x ft = 42ft
x + 3x + 2x = 42
6x = 42 =======> x = 42/6 = 7 ft
x = 7ft=====> 2x = 14ft ============> 3x = 21 ft
now the first rectangle will be of dimensions of 7 ft by 50 ft ====> 350 ft2
the second rectangle will be of 14 ft by 50 ft ========> 700 ft2
the third rectangle will be of 21 ft by 50 ft ========> 1050 ft2
so the total Field area is : 350 +700 +1050 = 2100 ft2
