Answer:
C
Step-by-step explanation:
The triangle inequality theorem tells us that if two sides of a triangle are known (let it be side a and b), we can know the length of range of third side (side c). By:
a-b< c < a+b
So sides are given 29 and 40.
Sum is 29 + 40 = 69
Difference is 40 - 29 = 11
Hence, the third side would be BETWEEN 11 and 69
C is the correct choice.