This house looking ruler makes an easy job of squaring up Triangles. The Top Half works like a 4 1/2" Triangle Square Up. This portion is great to square up Half Triangle Squares, Quarter Triangle Squares, and Tri-Square Patches. Turn the ruler around and the Square up any patch to 6 1/2" inches.
https://www.quiltinaday.com/shoponline/ruler/The-Double-Square-Up-by-Quilt-in-a-Day/198527
or https://amzn.to/2Tn2GYm
