Polylengths are what type of shapes compared to perimeters?

• A. Perimeters are open shapes and polylengths are closed
• B. Perimeters are 2D only
• C. Polylengths are open shapes, perimeters can be closed
• D. Polylengths cannot be split

Answer: (C)

The key idea is how length is defined for different kinds of shapes. A polylength measures the total length along a broken line made of straight segments, and that path can start at one point and end at another, so it is open. A perimeter, by contrast, is the full distance around a closed shape—you travel around the boundary and return to where you started, so it is closed. So polylengths correspond to open paths, while perimeters describe closed boundaries. That’s why describing polylengths as open shapes and perimeters as capable of being closed captures the distinction.