You have to make sure it is a triangle by adding the smallest and the medium sides, if the result is greater than the bigger side then it is a triangle.
you then use the Pythagorean theorem to check if the triangle is a right triangle, acute, or obtuse. If [tex]c^{2}[/tex] = [tex]a^{2} +b^{2}[/tex] then it is a right triangle. If [tex]c^{2} >a^{2} + b^{2}[/tex] then it is an obtuse triangle. if [tex]c^{2} < a^{2} +b^{2}[/tex] then it is an acute triangle.
[tex]10^{2}[/tex] _ [tex]3^{2} + 8^{2}[/tex]
9+64_100
70_100
70<100
in this case [tex]c^{2}[/tex] is greater than [tex]a^{2} +b^{2}[/tex] therefore, is it an obtuse triangle.