There is perfect unanimity as to the standard angle (i.e., the right angle) and practical unanimity as to its subdivision, for the subdivision into grades, etc., once favored by the French, is now abandoned.

1 minute of angle or arc

=

60 seconds.

1 degree " " " "

=

60 minutes.

90 degrees" " " "

1 right angle or ¼ of circumference.

Radian " " " "

=

arc same length as radius.

" " " " "

=

57.295779513082°.

Length of arc of 1°

=

0.017453292520.

Length of arc of 1'

=

0.000290888209.

" " " " 1"

=

0.015707963268.