a hoop has a diameter of 18"
The standard diameter of a basketball rim is 45cm.
It is 144.5 cm.
According to the regulation hoop diameter is 18 inches (inside the rim). Other sizes are available for practice or games other than regulation basketball. Use a search engine to find "basketball" +"hoop diameter".
it is 18 inch diameter
The hoop is 18 inches / 457.2 mm in diameter.
The diameter of an official NBA basketball hoop is 18 inches, about an inch less than twice the diameter of a men's ball. Other sizes are available for practice or games other than regulation basketball.
The hoop is 18 inches in diameter.