What collections of three side lengths can be used to form a triangle? a. 3 ft, 6 ft, 10 ft b. 3 ft, 6 ft, 9 ft c. 4 ft, 9 ft, 6 ft d. 10 ft, 5 ft, 4 ft

The two smallest sides need to add to be bigger than the biggest side. 

3+6=9 9 is not bigger than 10. This is not a triangle.

3+6=9 9 is not bigger than 9. This is not a triangle. 

4+6= 10 10 is bigger than 9. This is a triangle. 

5+4=9 9 is not bigger than 10. This is not a triangle.

"C" is the correct answer.

I hope this helps!
~kaiker

Provide an equation