The effect of error in a measured angle decreases with increasing length of sight distance

The statement is referring to the concept of surveying and measurement errors. Here's a step-by-step explanation:

1. In surveying, the sight distance is the distance between the surveying instrument (like a theodolite) and the point being measured.

2. An error in the measured angle can occur due to various reasons such as instrument calibration errors, operator errors, or environmental factors.

3. The effect of this angle error is more pronounced when the sight distance is short. This is because a small error in the angle can result in a large displacement at the point being measured.

4. As the sight distance increases, the same angle error results in less displacement at the point being measured. This is because the angle error is spread over a larger distance.

5. Therefore, the effect of an error in a measured angle decreases with increasing length of sight distance.

6. However, it's important to note that while the relative effect of the angle error decreases, the absolute error in the position of the point being measured may still be significant. Therefore, it's always important to minimize measurement errors as much as possible.