An angle for which the measure is between 0° and 90° is called an acute angle.
An example of such an angle is shown below:
Hence, since the angle 42° falls in this range, it is an acute angle.
An angle for which the measure is between 90° and 180° is called an obtuse angle.
An example of such an angle is shown below:
The angle 126° falls in this range, hence, it is an obtuse angle.
An angle whose measure is 180° is called a straight angle.
Hence, the angle 180° is a straight angle.
An example is shown below:
An angle whose measure is 90° is called a right angle.
Hence, the angle 90° is a right angle.
An example is given below:
