The determination of lengths and distances that are physically inaccessible or impractical to measure directly can be achieved through the application of geometric principles. This method leverages the properties of proportionate relationships between corresponding sides of triangles with identical angle measures. By establishing these relationships, unknown dimensions can be calculated based on known measurements within a system of scaled figures. For example, the height of a tall structure can be found by comparing its shadow length to the shadow of an object of known height, given that both shadows are cast at the same time and location, ensuring similar angular relationships.
This technique offers significant advantages in various fields, including surveying, construction, and navigation. Its non-invasive nature makes it particularly useful in situations where direct measurement is hazardous or impossible, such as determining the height of a cliff or the width of a river. Historically, this principle has been employed for centuries, allowing for the creation of maps, construction of large-scale infrastructure, and advancements in understanding spatial relationships, well before the advent of modern electronic tools.