Robin Ruth Rulers Angle Ruler- Straight edge ruler with all of the angles needed for every Robin Ruth Design patterns, each sold separately. Angles are in the middle of the ruler to make compass construction easier. These angles are commonly used in lots of different quilt blocks, so having them all in one place makes this a great tool. Measures approximately 6 in. x 14 in. Angles range from 33. 75 to 90 degrees.