I made a Paddle Wheel quilt in which all edges of the block ended on the bias. The tips of each corner had to exactly match the next block.
I put my 12 1/2 inch ruler on my ironing board, drew around that with a ball point pen, then drew a one inch line radiating from each corner. I laid the block on that, lined up the corners with the radiating line, starched it in the correct position and pressed it with a hot iron. Then I could go to the cutting board and cut it square; all the seams ended up right in the corner like they were supposed to. The blocks stayed square and the quilt turned out great.