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.

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. Image caption, ...

Where Pi (π) is of course the number and r is the radius of the circle. ... If the area is also supposed to be πR 2, I can make a plot of area vs. diameter squared.

Everybody knows what the term turning radius means, but what we are actually referring to, as in Jeff Hemmel’s feature article “Jet Drive vs. Sterndrive,” is the turning circle.. When describing how ...