Final answer:
The ratio of x to 400 is 1 to 4. To find x in a proportion, set up a cross multiplication with the given ratios. Ratios are pivotal in solving problems related to scaling and unit conversions.
Step-by-step explanation:
The question asks us to find the ratio of x to 400. A ratio compares two quantities, and in this case, we need to determine what number x should be so that the ratio x:400 is equivalent to one of the given options: 5, 4, 50, or 25. The correct ratio is x to 400 is 1 to 4, which can also be written as 1:4 or 1/4.
To apply this in a proportion problem, such as 1:2=4:x, we can set up a proportion where each of the ratios is equivalent. We cross multiply to solve for x. Here, we'd have 1 * x = 2 * 4, which simplifies to x = 8.
The concept of ratios is also used in scaling and unit conversion problems. For example, if a scale dimension is 0.5 inches and the actual dimension is unknown, represented as x miles, we can write the ratio as 1 inch/2000 miles = 0.5 inches/x miles and solve for x.