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.

The formula for the area of the circle is 𝑨 = π𝒓². To work out the area of a circle: Find the value of the radius. If the diameter is given, this must be halved.

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.