Classification of Triangles on the basics of Angles –
Acute Angled –

In an Acute angled or acute triangle, each of the angles is less than 90⁰.
Obtuse Angled –

In an obtuse angled or obtuse triangle, one of the angles is greater than 90⁰.
Right Angled –

In a right angled or right triangle, one of the angles is a right angles, the side opposite to it is called the hypotenuse.