Answer:
1 < x < 19
Step-by-step explanation:
Triangle Inequality Theorem
Let y and z be two of the side lengths of a triangle. The length of the third side x cannot be any number. It must satisfy all the following restrictions:
x + y > z
x + z > y
y + z > x
Combining the above inequalities, and provided y>z, the third size must satisfy:
y - z < x < y + z
We are given the measures y=10, z=9. The third side must satisfy:
10 - 9 < x < 10 + 9
1 < x < 19
