I've made several other of her patterns and just used my regular rulers for flying geese and half and quarter square triangles. If you are going to make a quilt with the triangle-in-a square patch, I would get the ruler. There are lots of patterns that have this patch: 54-40, tennessee waltz, storm at sea to name a few.
The tri recs ruler and companion ruler (sold in a set) are pretty inexpensive. They are sold at JoAnn's and you can use your coupon. To make the triangle-in-a-square patch they are a necessity (imho). The angle for the triangle is 53.5 degrees, not 60. The only way to achieve this is to use this ruler or paper piece it.