This tutorial for a 3" Finished block. (This block could be done another way... this is just how I did it.)
Step 1 - Cut a 5" Square
Step 2 -Cut 5" Square into 4 triangles on the diagonal
Step 3 - Cut 4 .75" Square. (I folded it in half both ways for center reference)
Step 4 - Fold 4.75" Square in half - wrong sides together. This picture shows how the pieces will be laid out when sewn together.
Step 5 - Place one triangle on the back side of the folded square with raw edges together and with right sides of fabric together.
Step 6 - Place another triangle on the top side of the folded square with raw edges together and with right sides of fabric together.
Step 7 - This is how it should look before sewing it together. Sew along the short edge of the folded 4.75" square.
Step 8 - Do both sides of the 4.75" square in the same manner.
Step 9 - Open the triangles and prepare to iron them open.
Step 10 - Iron triangles so wrong sides are together.