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.

The constant π is traditionally defined as the ratio of a circle's circumference to its diameter. As I pointed out in the first installment of this series, the fact that this is well-defined (i.e ...

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 ...

The diameter, for its part, is 6 units long, as shown by the red dashed line. Thus, the circumference divided by the diameter equals 24/6, so pi equals 4 in taxicab geometry.

The diameter of the hexagon, for its part, is two times the circle’s radius, or 2r. Now recall that the perimeter of the hexagon underestimates the true circumference of the circle.