Find the diameter and the radius of a circle with a circumference of 465 cm. Give the answer to the nearest centimetre. Use π = 3۰142 or the π button on a calculator.

…and you can see that the ribbon is just over 3 times the diameter of 1 circle. This number, called π (or pi), is approximately 3.14. You have shown that the circumference of a circle is π × ...

How an ancient Greek mathematician calculated the Earth's circumference. In the mid-20th century, we began launching satellites into space that would help us determine the exact circumference of ...

Today is Pi Day, but you should stop celebrating it and instead use tau as your circle constant. Tau Day — the true holiday — is celebrated on June 28th.