Approximations for PI

Many different approximations for the actual value of pi have been proposed and used. For each of the following, determine their accuracy to the nearest percent:

• 256/81 [Egyptian value, 1700 BC]
• 22/7 [Egyption value, 1000 BC]
• 3+10/71 < Pi < 3+1/7 [Archimedes' approximation of a circle by a regular 96-gon]
• SQRT(10) [Ch'ang Hong, China, 125 AD]
• 31^(1/3)
• 666/212
• 355/113 Ch'ung-chih, China, 470 AD]
• 104348/33215
• One of the roots of 9x⁴-240x²+1492=0