Question 1096932
<br>(1) List all the ways you can add three of those numbers to get a sum of 19:
4+6+9
4+7+8
5+6+8<br>
There are three ways, corresponding to the three sides of the magic triangle.<br>
The numbers 4, 6, and 8 each appear twice in those sums; that means they must be in the three corners of the triangle (so they get counted twice -- once on each of two sides of the triangle).<br>
Once you have those numbers in the corners, there will be only one way to place the other three numbers to make the sum on each side equal to 19.