HOW DO I? Figure the size of HST (Half Square Triangles) needed to make Square-in-a-Square blocks using a unique size center square
1 Determine the finished size of the center square
This square measures 6 1/2, which is its CUT size. Therefore, sum the seam allowance (1/4" each side) and subtract 1/2" from the overall size to find the FINISHED size of 6".
2 Open Triangle Calculators in Notions — HALF SQUARE & CORNER
Choose half square triangles for this project to put the straight of grain on the outside of the block.
Quarter square triangles have stretchy, bias edges on the outside of the block. In contrast, Half square triangles avoid stretching because they place the straight grain on the outer edges.
The calculator determines the size of the square you need to get your half square triangles. Follow these steps:
In this example, the calculator figures that we need to cut a 5 1/8" square.
What will be the block's finished size?
3 Cut squares to size, then into half triangles
4 Assemble the Square-in-a-Square block