Question

The sides of a triangle are 10, 14, 18 what tie of triangle is it

Answer 1

Let "a", "b" and "с"  be sides of the triangle ("с" is the longest side). The triangle will be:
right if       a² + b² = c²
аcute if     a² + b² > c²    
obtuse if   a² + b² < c²    

We have a=10, b=14 and c=18

a² + b² = 10² + 14² = 100 + 196 = 296
and
c² = 18² = 324

296 < 324   ⇒  obtuse triangle.