14 CUBIC SYSTEM. FIG. 14. FIG. 15. 48. The form 101 (fig. i 6 ) ha3 twelve laces, and is called a dodecahedron. G = 60°. Any two alternate faces, meeting at their acute angles, make with each other an angle of 90°. 49. In a combination of the forms loo and 101 (fig. it), the faces of 101 truncate the edges of loo. A normal to any face d of the form 101 makes an angle of 45° with normals to each of the adjacent faces a of the form 100 an angle of 135° with normals to each of the opposite faces, and an angle of 90° with normais to each of the two remaining In a combination of the forms in f + d (fig- 18), the faces of 101 trun cate the edges of m. mi A ™ n 'i rmal t0 any face d of the form 101 makes an angle of 35° ie' with nor mals to each of the adjacent faces o of the form in; an angle of H4° 44'with normals to each of the opposite £ and an angle of 90° with nopals to S ot the four remaining faces. oil FIG. 17. *fl a' d'' a FIG. 18. FIG. 19.
