Question 474669
You only use Pythagorean theorem if you want to show whether a triangle is a right triangle. For example, an equilateral triangle with sides 1,1,1 does not satisfy the Pythagorean theorem (1+1 is not equal to 1)


You have to use the triangle inequality which says that for a triangle, the sum of any two sides is always larger than the third side. Here, 2+3 is less than 6, so this violates the triangle inequality, hence a triangle with sides 2,3,6 cannot exist.