6.1 Angles and Their Measure/55

${\frac {-\pi }{2}}$ $\cdot$ Failed to parse (Conversion error. Server ("https://en.wikipedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\frac {{\cancel {2}}\cdot 2\cdot 5\cdot 3\cdot 3}{\pi }}}