Is the hight of a basketball ball hoop negative value

No way
If you are measuring something it should never be in the negative form, always positive anything you measure is positive

Non metal is an element or substance that is not a metal metal is a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivitymetalloid is an element (e.g., germanium or silicon) whose properties are intermediate between those of metals and solid nonmetals. they are electrical semiconductors.