For second-order class II maximum triangle closure, which value is correct?

• A. 3 arcseconds
• B. 5 arcseconds
• C. 10 arcseconds
• D. 1 arcsecond

Answer: (B)

Triangle closure in a second-order class II network checks how much the sum of the three measured interior angles of a triangle can deviate from 180 degrees due to observation errors. For this precision level, the standard allowance—the maximum misclosure—is 5 arcseconds. That means the three angles should add up to 180 degrees within 5 arcseconds. Among the given values, 5 arcseconds matches this tolerance, while 1" and 3" are tighter than needed and 10" would be looser than the standard. So the correct value is 5 arcseconds.