Respuesta :

Answer:

25.796... km

Step-by-step explanation:

We are given that:

  • Circumference: 81 km

Formula of circumference:

  • 2πr or πd

Thus, we can rewrite the circumference as:

  • 2πr = πd = 81 km

Since we are asked to determine the diameter, it is recommended to use the formula (πd). Therefore,

  • πd = 81 km

Divide π both sides to isolate the diameter:

  • ⇒ πd/π = 81 km/π
  • ⇒ d = 81 km/π

Substitute π as 3.14 and simplify:

  • ⇒ d = 81 km/3.14
  • d = 25.796... km

Therefore, the diameter of the circle is 25.796... km.