(i) In addition to degree and radian, there is a third measurement of an angle is called the grade.
(ii) When a right angle is divided in to 100 equal parts, each part is defined as "grade".
(iii) The symbol used is g (i.e, g as an exponent).
(iv) Each grade is sub-divided into 100 minutes (denoted as 100').
(v) Each minute is sub-divided into 100 seconds(100").
(vi) i.e, 1 right angle(or 90°) = 100 grades = 100g
(vii) 1g = 100'
(vii) 1' = 100"
Relation between 3 measures of an angles
If D is measure in degrees in, G in grades and r in radians, then
Note:
While the symbols °, c and g are used to indicate angles in degrees, radians and grades respectively, if there is no symbol it is assumed the measure of an angle is in radians.
How many grades constitute a circle ?