This page contains a list of corrections to the first printing.
(Most of these, I understand, are corrected in the second printing, but
I haven't personally seen a copy yet.) If you find any errors not
listed here, please let
me know.
Chapter 21. The Fourth Dimension
Exploration 21D, the 600-cell, stops too soon in error.
On the triacontahedron's rhombi, add r1s and y2s as the slanting
edges of 30 rhombic pyramids, i.e., 60 tetrahera. Then connect their
peaks using 60 b2s (that outline an icosidodecahedron) to complete
60 tetrahedra around the 5-fold axes and 20 over the 3-fold axes. (Vin
de Silva, Nov. 2001)
Answers
-
p. 231, typo, 12.3 Q1 a, truncated tetrahedron has three 2-fold
axes.
-
p. 235, typo, Expl. 13C, denominator 1- tau squared beta should
be 1- tan squared beta.
-
p. 237, A better answer for Challenge 15.1 is a b2-y1-y1 triangle,
with area 0.25 b1^2. (Bob Mead, Jan 2002)
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p. 241, typo, Expl. 16G should refer to Activity 21.4 (not 21.3).
-
p. 241, A better answer for Challenge 17.1 is a low slanted triangular
prism built on a b2-y1-y1 triangle, using either four b1s
or four y1s for the side edges. The height is the same in either
case, and the volume is approximately 0.0773 b1^3. (Bob
Mead, Jan 2002)
Index and Table of Parts Needed
-
120-cell: The parts count should say "120 r1 and 120
r2",
not "180 r1 and 180 r2". (Casey Mann,
Nov 2002)
-
31-zone zonohedron: The parts count is for a hemispherical dome;
double it if you want to make the entire ball (which would have to be suspended,
as one face can't support the whole weight). (Kevin
Perkins, Jan 2001)
-
600 Cell: 120 b2, 120 y2, 72 r1, 72 r2,
75 balls, for the complete model described above. (Vin
de Silva, Nov. 2001)
-
compound of 3 cubes: The parts count should say "12 b3",
not "12 b2". (Kevin Perkins,
Jan 2001)
-
comound of icosidodecahedron and rhombic triacontahedron: Should
say "120 b2, 60 r1, 60 r3". (Dave Keenan,
Nov. 2001)
-
truncated cuboctohedron: 24 bx, 48 gbx, 48 balls.
(Kevin
Perkins, Jan 2001)
