Cutting Triangles HALF-SQUARE TRIANGLES The straight grain of the fabric is located on the short sides of the triangle. Use half square triangles for the corners of the quilt. QUARTER- SQUARE TRIANGLES The straight grain of the fabric is located on the long side of the triangle. Use quarter square triangles for the sides of the quilt. CUTTING LARGE TRIANGLES Square the edge of the fabric (refer to Rotary Cutting lesson) Using two rulers for the extra wide strips, cut the fabric into strips.