Question

Please help me out on this one

Try this triangle: 3ft, 4ft, and 1 ft

Is the first plus second greater than the third? Is 3+4> 1? ________
Is the second plus third greater than the first ? is 4+1 >3?___________
Is the third plus first greater than the second? Is 3+1 >4_________
Can it make a triangle? Explain why?

Answer 1

9514 1404 393

Answer:

yes, yes, no; No

Explanation:

We have to assume you have no trouble with single-digit addition and comparison of two numbers.

3+4 > 1 ⇒ 7 > 1 . . . . yes

4+1 > 3 ⇒ 5 > 3 . . . . yes

3+1 > 4 ⇒ 4 > 4 . . . . no

These lengths will not make a triangle because the triangle inequality is not satisfied.

_____

Additional comment

You will notice that we found the result of interest when we added the two smallest numbers (1 and 3) and compared the sum to the largest number (4). This is a shortcut you can use for any "will these make a triangle" question. You don't need to bother comparing larger numbers to smaller ones. You already know they are larger.