Step 1
According to the first triangle inequality theorem, the lengths of any two sides of a triangle must add up to more than the length of the third side. This means that you cannot draw a triangle that has side lengths 2, 7 and 12, for instance, since 2 + 7 is less than 12.
Step 2
For sides 29 , 40 and x
x must be less than 29 + 40 = 69. x must be less than 69.
x must also be greater than 11
Final answer
11 < x < 69
Option C
