3. Proportions and the American Flag According to The Flag Book of the United States, the official U.S. flag must have a ratio of 19 to 10 for the length to the width. If a souvenir maker makes a US flag that is 57 cm long, in order for it to be an official U.S. flag what would its width have to be?
Think about your school pictures today and tomorrow. You might get some wallet-size photos, some 4x5 photos for relatives, and even some 8x10s to frame and hang in the living room. These different size pictures are all pictures of you. Each picture looks like you because the features of your face are still in the same proportion to one another. When a photograph is taken, the camera and the developer shrink (or enlarge) the image proportionally. That is, all dimensions are increased or decreased by the same factor. So, if your face is 2.5 inches from hairline to chin in the 4x5 photo, it will be twice as long (5 inches) in the photo with dimensions twice as long (8x10). It will be half as long (1.25) inches in a photo with dimensions half as large (2 x 2.5).
