Answer:
4.0 < x < 12.0
Explanation:
In a triangle, the length of any side must be greater than the difference of the lengths of the other two sides and less than the sum of the lengths of the of the two sides.
That means is to add the two given lengths. x must be less than this sum.
4.0 + 8.0 = 12.0
x must be less than 12.0
Subtract the two given lengths. x must be greater than this difference.
8.0 - 4.0 = 4.0
x must be greater than 4.0
Answer: 4.0 < x < 12.0