Oma for four,
Look up Rhonda's tutorial for half square triangles. It is in the topic log section. Her method takes all math out of quilting. She sews two, 2-1/2 strips together. One strip of each color you want to use in you hst (half square triangle). Press to the dark. Make a 3 inch square template. Here comes the great part! Place two points of that square template on the seam line of the two strips you sewed together. Diamond fashion. Cut. Look at what you've got!! A perfect half square triangle! Hope this helps.