1 answer
(click or scroll down)
The third side of a triangle must be greater than the absolute difference of the other two sides, and less than the sum of the other two sides.
So in this case, the third side must be greater than |11-7| = 4 and less than 11+7 = 18.
Therefore, the range of values for the third side of the triangle is 4 < x < 18.