What do you do if you want
to measure and you have
no ruler handy?
Use something you always
have with you.

  If you wanted to measure the book
  with a ruler it would be 6 inches
  tall. 

  If no ruler was handy, you could use
  the space between two knuckles on
  your finger to find about how tall
  the book is in inches. 

  If you wanted to measure the ball
  with a ruler it would be 4 inches
  wide. 

  If no ruler was handy, you could use
  the space between two knuckles on
  your finger to find about how wide
  the ball is in inches. 

  If you wanted to measure the
  tent with a ruler it would be 2 feet
  tall.  

  If no ruler was handy, you could use
  your arm to measure about how tall 
  the tent is. 

  If you wanted to measure the
  couch with a ruler it would be 3 feet
  wide.  

  If no ruler was handy, you could use
  your arm to measure about how wide
  the couch is. 

If you don't have a ruler, there are other ways to measure.