Obtuse angle: an angle whose measure is more than `90^@`but less than `180^@`is called an obtuse angle (Fig.11.27).

An obtuse angle is

An obtuse angle is

Acute angle an angle whose measure is greater than 0^(@) but less than 90^(@) is called an acute angle.

An angle which measures more than 180^(@) but less than 360^(@) , is called

Reflex angle an angle whose measure is greater than 180^(@) and less than 360 's called a reflex angle.

Obtuse triangle a triangle whose one angle is obtuse is called an obtuse-angled triangle or an obtuse triangle.

A reflex angle measures more than 90^(@) but less than 180^(@) more than 180^(@) but less than 270^(0) more than 180^(@) but less than 360^(@) none of these