List three numbers from one to 20 then write in equality to prove whether those side lengths make a triangle

Answer 1

Let's consider three numbers from one to 20: 5, 12, and 18.

To prove whether these side lengths make a triangle or not, we need to check if the sum of any two sides is greater than the third side. Let's perform this check:

1) Sum of 5 and 12 is 17. Is 17 greater than 18? Yes.
2) Sum of 12 and 18 is 30. Is 30 greater than 5? Yes.
3) Sum of 5 and 18 is 23. Is 23 greater than 12? Yes.

In all three cases, the sum of any two sides is greater than the third side. Therefore, using the numbers 5, 12, and 18, we can form a triangle.