An engineer's scale is a tool that looks like a ruler but is used to measure things that are very big or very small. It is called an engineer's scale because it is commonly used by engineers who need to make precise measurements for buildings, bridges, and other structures.
The scale has two sides, one for measuring in feet and one for measuring in inches. Each side is divided into smaller sections, with each section representing a certain length. The lengths that are used on the scale are usually based on a ratio, such as 1:10 or 1:20.
To use the engineer's scale, you need to first determine the scale ratio that you need. Then, you line up the start of the scale with one end of the object you want to measure, and then count the number of sections on the scale that match the length of the object. The scale can also be used to draw accurate plans and sketches of structures, as long as you use the correct scale ratio to represent the real-world measurements.