The blue part is approximately 1/5 of the total area. A standard U.S. flag is 1.9 unit by 1 unit. The blue part is 7/13 unit by 0.76 unit. The area of the blue part is 0.409 sq. units. The area of the flag is 1.9 sq. units. 0.409/1.9 = 0.215 0.215 is approximately 1/5
