What Is an Obtuse Angle? (Mathematics Lesson)
What Is an Obtuse Angle?An obtuse angle is an angle greater than 90° and less than 180°.
An obtuse angle is greater than a right angle and less than a straight line.
Real Examples of Obtuse AnglesThe angles below are all obtuse angles:
NoteWHAT'S IN A NAME?
Obtuse comes from the Latin word 'obtusus' meaning "blunt".
An obtuse angle makes a blunt point.
EUCLID AND OBTUSE ANGLESEuclid defines angles in his book, Elements.
Definition 11: "An obtuse angle is an angle greater than a right angle".