I want to put a triangle on each end of a table runner and can't figure out how big to cut a square. Can someone please help me? It is 16 1/4 inches long x 43 1/8 wide. Thanks. I did the 16 1/4 x 1.414 plus 1.25 (I think that's the formula)and it comes out 24 1/4. This seems way to big to me. I need your help. Thanks.