I need help with #51 ASAP … please help me with it I don’t understand it please and thank you

Ineed with number 17 i don’t get it at alll

Triangle inequality theorem state if each set of three numbers can be the lengths of the sides of a triangle. 1. 9, 8, 22. 2. 5,10,12. 3. 7,10,22. 4. 4,11,12. 5. 11,9,10. 6. 10,4,19. 7. 3,12,10. 8. 4,3,2. 9. 6,5,13. 10. 7,12,20. me .

What is not true about kl and mn? what is mn? (show your work)