Equations and Figures with PI

DIAMETERxPI=CIRCUMFRENCE

(RADIUS^2)xPI=AREA

2xPIxDiameter of elephant's foot=Its height

Hat size=PIxCircumfrence of head (rounded to nearest 1/8 inch)

1 millionth digit of PI=1

PI/2=2x2x4x4x6x6x8x8.../1x1x3x3x5x5x7x7...

PI=24 arctan(1/8)+8 arctan(1/57)+4 arctan(1/239)

PI/4=3 arctan(91/4)+arctan(1/20)+arctan(1/1958)

e^(PIxi)=-1

PI/4=5 arctan(1/7)+2 arctan(3/97)

PI/2=3/2x5/6x7/6x11/10x13/14/17x18x19/18x23/22...

(PI^2)/6=1/1^2+1/2^2+1/3^2...

1-sin=(1-(2a/PI))^2 (1+(2a/3PI))^2 (1-(2a/5PI))^2 (1+(2a/7PI)^2...

(PI^3)/32=1/(1^3)-1/(3^3)+1/(5^3)-1/(7^3)...