Basics

• pi is the ratio of circumference to diameter
• Pi is an irrational number, approximately equal to 3.14159.
• $A=$$\Pi*$$r^2$

  Example:A=3.14*2^2
• $A=$$\pi/4*$$d^2$

  Example: A=3.14/4*4^2
• $r=$$d/2 >r^2=$$(d/2)^2=$$d^2/4$
• $D=$$2*$$A/\pi$

  D=
• $R=$$A/\pi$

  R=
• $M=$$2*$$\pi*$$r*$$h$

  $G=$$\pi*$$r^2$

  O=$2*$$G+$$M$
• U=$\pi*$$d$

  U=$\pi*$$2*$$r$