● The measure of an angle is the amount of rotation performed to get the terminal side from the initial side.
● There are several units for measuring angles.
●The definition of an angle suggests a unit, viz. one complete revolution from the position of the initial side as indicated in Fig opposite
● If a rotation from the initial side to terminal side is `(1/360)^(th)` of a revolution, the angle is said to have a measure of `color{blue}{ul"one degree"}`, written as `1°.`
● A degree is divided into `60` minutes, and a minute is divided into `60` seconds.
● One sixtieth of a degree is called `color{blue}{ul"a minute"}`, written as `1′`.
● one sixtieth of a minute is called `color{blue}{ul"a second"}`, written as `1″.`
Thus, ` \ \ \ \ \ \ \ \ \ \ \ \ \ \ \color{green} (1° = 60′, \ \ \ \ \ \ \1′ = 60″)`
Some of the angles whose measures are `360°,180°, 270°, 420°, – 30°, – 420°` are shown in Fig 3.3.
● The measure of an angle is the amount of rotation performed to get the terminal side from the initial side.
● There are several units for measuring angles.
●The definition of an angle suggests a unit, viz. one complete revolution from the position of the initial side as indicated in Fig opposite
● If a rotation from the initial side to terminal side is `(1/360)^(th)` of a revolution, the angle is said to have a measure of `color{blue}{ul"one degree"}`, written as `1°.`
● A degree is divided into `60` minutes, and a minute is divided into `60` seconds.
● One sixtieth of a degree is called `color{blue}{ul"a minute"}`, written as `1′`.
● one sixtieth of a minute is called `color{blue}{ul"a second"}`, written as `1″.`
Thus, ` \ \ \ \ \ \ \ \ \ \ \ \ \ \ \color{green} (1° = 60′, \ \ \ \ \ \ \1′ = 60″)`
Some of the angles whose measures are `360°,180°, 270°, 420°, – 30°, – 420°` are shown in Fig 3.3.