Johnson Solids (Page 1)

(box: x-ray)  (F: faces)  (slider: perspective)  (image: L=rotate R=zoom)  (M: metrics)

(J6) Pentagonal Rotunda
Vertices:  20  (10[3] + {5 * 2}[4])
Faces:17  ({5 * 2} equilateral triangles + {5 + 1} regular pentagons
    + 1 regular decagon)
Edges:35
Symmetry:  5-fold Pyramidal  (C5v)
(values below based on edge length = 1)
Volume:(45+17*sqrt(5))/12    ≈6.9177629681247020699