



 
Hi Alfred, You can use two triangles to make a rectangle which is two less than the number of sides. A pentagon can be made by 3 triangles, a hexagon can be made by 4 triangles, etc. To find the sum of the interior angles for any polygon use (n2)*180 degrees where n is the number of sides. Janice  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 