Can 7, 9 and 15 make a triangle

Step by step

The question

Question: can sides of 7, 9 and 15 make a triangle?

For a triangle, the two short sides together must be longer than the longest side.

Else they cannot meet.

1 Add the two short sides

The longest side is 15.

We lay it down first.

The two short sides are 7 and 9.

Together: 16.

2 Compare with the longest

Swing them up from the ends.

16 is more than 15, so they meet at the top.

So yes: they make a triangle.

3 Check

Let's check the other two pairs: 7 plus 15 is 22, and 9 plus 15 is 24.

Both are more than the third side.

So only the short pair decides.

So the answer is right!

Let's look back.

First: add the two short sides.

Then: compare with the longest.

Last: check.