Circle a triangle whose base has the length of the circle's circumference and whose height equals the circle's radius, which comes to multiplied by the radius squared: Equivalently, denoting diameter by "d", that is, approximately 79% of the circumscribing square (whose side is of length "d"). The circle is the plane curve enclosing the maximum area for a given arc length. This relates the circle to a problem in the calculus of variations, namely the isoperimetric inequality. Equation of a circle<br> In an "x"–"y" Cartesian coordinate system, the circle with centre coordinates ("a", "b") and radius "r" is the set of
The Play That Goes Wrong 27 previews. A touring production began in Australia at the Comedy Theatre in Melbourne from February 2017, before heading to Adelaide, Sydney, Canberra, Brisbane and Perth. The play is touring North America, starting in September 2018 in Pittsburgh, Pennsylvania. "The Play That Goes Wrong" received positive reviews. Quentin Letts of the "Daily Mail" gave it five stars out of five, saying "As it all goes awry it becomes hard not to gas yourself with laughter. At one point I feared I was going to hyperventilate." Tim Walker of "The Telegraph" gave it four out of five stars and called it