Question

The angles of some triangles are given below. Classify each triangle acute angle, obtuse angled or right angled on the basis of its angles.
(i) ${90}^{\circ },{45}^{\circ },{45}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$
(ii) ${80}^{\circ },{60}^{\circ },{40}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$
(iii) ${120}^{\circ },{50}^{\circ },{10}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$
(iv) ${60}^{\circ },{60}^{\circ },{60}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$
(v) ${92}^{\circ },{50}^{\circ },{38}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$
(vi) ${90}^{\circ },{35}^{\circ },{55}^{\circ }\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Answer 1

i) Right-angled isosceles because one angle is ${90}^0$

ii) Acute angled, as all angles are lesser than ${90}^0$

iii) Obtuse angled, as ${120}^0>{90}^0$

iv) Equilateral, as all angles are equal

v) Obtuse angled, as ${92}^0>{90}^0$

vi) Right angled, as one angle is ${90}^0$