Question

3 questions about edge-angle relationships. Please help me!!

Answer 1

For question 1, the triangle inequality will come in handy, which says
The sum of any two sides of a triangle must be greater than the third side.
A corollary would be:
The sum of the shorter sides of a triangle must be greater than the longest side.

For questions 2 and 3, is there a restriction that the lengths have to take on integer values?

Answer 2

1) if we use triangle inequality; 8<x<18 right? but the answer key says answer is 11 so we have to consider ABC triangle as well.

for 2 and 3 i've written all the info there is no restriction