Question

which of the following sets could not be the lengths of the sides of a triangle (5,6,12) (5,7,10) (4,4,5) (4,5,5)

Answer 1

Remember that a+b<c in a triangle. So, the longest side must be greater than the other two added together.

B is fine because 5+7>10

C is ay-okay, because 4+4>5

D is alright, because 4+5>5

buuuut A is 5+6, and that's less than 12, so A is the one that can't be the lengths of the sides of a triangle.