The acute triangle is defined by the condition,
[tex]a^2+b^2The obtuse triangle is defined by the condition, [tex]a^2+b^2>c^2[/tex]
Here, we have,
[tex]\begin{gathered} 19^2=361 \\ 12^2=144 \\ 15^2=225 \\ 12^2+15^2>19^2 \end{gathered}[/tex]
Thus, the triangle is an obtuse triangle.
