1 Full revolution = 360 °
Degree
We measure angles in term of degrees.
1 revolution = 360 °
1/2 revolution = (360°)/2 = 180°
1/4 revolution = (360°)/4 = 90°
So,
Right angle = 1/4 revolution = 90°
Straight angle = 1/2 revolution = 180°
Acute Angle
Acute angle is less that right angle.
∴ Acute angle < Right Angle.
Acute angle < 90°
Obtuse Angle
Obtuse angle is greater than right angle, but smaller than straight angle.
Right angle < Obtuse angle < Straight angle.
90° < Obtuse angle < 180°
Reflex Angle
Reflex angle is an angle greater than straight angle.
Reflex angle > Straight angle
Reflex angle > 180°
To summarize,
Right angle = 90°
Straight = 180°
Acute angle < 90°
Obtuse angle > 90° & Obtuse angle < 180°
Reflex angle > 180°
