Math Open Reference
From Latin: obtusus - "blunt"
whose measure is greater than 90° and less than 180°
below by dragging the orange dot at A and see how the angle
ABC behaves. Note that it is obtuse for all angles greater than 90° and less than 180°
Not to be confused with an
which has one obtuse interior angle.
Types of angle
Altogether, there are six types of angle as listed below. Click on an image for a full description of that type and a corresponding interactive applet.
Less than 90°
Between 90° and 180°
Between 180° and 360°
Other angle topics
Interior of an angle
Alternate interior angles
Alternate exterior angles
Interior angles of a transversal
Exterior angles of a transversal
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