Which of the following could not be a value of n?

A. 7
B. 10
C. 13
D. 22

Question

Which of the following could not be a value of n?

	A.	7
	B.	10
	C.	13
	D.	22

anonymous · Answer

attachment

terenzreignz · Answer

Triangle inequality :)
Here's a direct approach... if you're given two sides of a triangle, say, a and b,  the third side MUST fall within this (open) interval:
$$\Large (|a-b| \ , \ a+b)$$

terenzreignz · Answer

In this case, your a and b (it doesn't really matter which is which) are 13 and 9.

What's the interval?

anonymous · Answer

im not sure. =/

terenzreignz · Answer

Okay, your a is 13, your b is 9.

What is |a - b| ?

anonymous · Answer

4

terenzreignz · Answer

that's right :)
Now what's a+b?

anonymous · Answer

22!

terenzreignz · Answer

That's right :)
So, the possible values for n (the third side)
must be STRICTLY between
4 and 22.

One of these choices... isn't :D

terenzreignz · Answer

Which is it?

anonymous · Answer

22 !?

terenzreignz · Answer

Yes. 22 is not STRICTLY between 4 and 22.
So that's the impossible value for n :D

anonymous · Answer

ahh. thank you so much! i appreciate it when people walk me through it! i typed the whole equation in a calculator, and it didnt come up right, so i had to question it before you explained it further. thank you so much!!

terenzreignz · Answer

No problem :)