Final answer:
To determine the length of Javier's scale model of the USS Tennessee submarine, set up a proportion using the scale (1 inch = 20 feet) and solve for the model length, which results in a model that is 28 inches long.
Step-by-step explanation:
Javier is building a model of the USS Tennessee submarine, which is 560 feet in length, and he is using a scale where 1 inch represents 20 feet. To find the length of his model, we use the scale to set up a proportion.
Because 1 inch represents 20 feet, we can set up the following equation: 20 feet / 1 inch = 560 feet / x inches, where x is the length of the model submarine in inches.
To solve for x, we cross-multiply and get x = 560 feet / 20 feet per inch.
This simplifies to x = 28 inches. Therefore, the length of his model should be 28 inches long.