## Errata (Gold Cover Draft)

This web page lists errors that have been discovered in the draft version (gold cover) of the text Exploring Geometry , by Mike Hvidsten.  Please note that any changes involving mathematical notation are expressed in TeX form.
If you discover errors other than those listed, please email them to hvidsten(at)gustavus.edu

 Page(s) Line(s) Description Date Discoverer 13 25 Replace "Let x be the ratio of AB to AG." by "Let x be the length of AG." 9-1-2004 M Hvidsten 65 9 Insert a left parend before the phrase "refer to Fig 2.9)" 9-21-2004 P Nichols 67 14 (Ex 2.2.3) Replace "exactly three sides" with "three (or more) sides" 9-27-2004 B Zirbes 87 5,6 (Ex 2.5.5) The overlines should be removed from the fractions defining sin and cos. 9-16-2004 Bill Stegemoller 160 9 Add the line "It suffices to prove the result for the case where B is outside c. (Why?)" after the sentence "Given a circle ... radius OA." 9-1-2004 M Hvidsten 160 16 Replace "\Delta CGB and \Delta CEO" by "\Delta GBO and \Delta EOB" 9-1-2004 M Hvidsten 160 15-16 Replace "and congruent" by "are congruent" 9-1-2004 M Hvidsten 178 31 (-2) Add ", where P' is the reflection of P onto l." at the end of the sentence "... P'Q." 9-11-2004 M Hvidsten 179 10 Replace "In this figure PR" by "In this figure P'R" 9-11-2004 M Hvidsten 179 12 Replace the entire text of the hint with "[Hint: Use the distance-preserving property of a folding (reflection).]" 9-11-2004 M Hvidsten 218 23 Replace "the fourth condition" with "the second condition" 11-17-2004 P Nichols 228 4 (Ex 5.7.1) Replace "is a translation if" with "is a translation if and only if" 11-17-2004 P Nichols 248 Paragraph 4 There is a section of text that did not print. The paragraph should read "First, we note that all translations in $\mathcal{T}$ must be generated by integer combinations of $v$ and $w$. For suppose $T_z$ was a translation with $z$ not an integer combination of $v$ and $w$. The two vectors $v,w$ define a parallelogram in the plane and the set of all integer combinations of $v,w$ will divide up the plane into congruent parallelograms." 11-17-2004 P Nichols 252 14 The first fraction should be "\frac{360}{6}" 11-29-2004 P Nichols 240-241 All references to the "dihedral group of order n" should be replaced by "dihedral group of order 2n". 11-15-2004 Geometry class at Gustavus - fall 2004 328 6 Replace "exercise 5.7.2" with "exercise 5.7.3". 9-21-2004 M Hvidsten 329 10 The term " PP' " should be overlined. 9-21-2004 M Hvidsten 331 last line Replace "the fact" with "assume" 9-27-2004 M Hvidsten 332 11 Replace "will map the disk to f" with "will map the disk to c" 11-29-2004 M Hvidsten 343 19,20 in Ex 8.6.4 Replace "radius c" with "radius hr" and Replace "sinh(c)" with "sinh(hr)" 9-27-2004 M Hvidsten 344 4 Delete "Hint: " 9-27-2004 M Hvidsten 347 13 In the expression for x, the numerator should be "2u" 9-27-2004 M Hvidsten 348 6 Replace "Given a triangle," with "Given a doubly limiting triangle," 9-27-2004 M Hvidsten 377 8 in Ex 9.6.6 Replace "N_1(A)=3, N_2(A)=3^2, N_3(A)=3^3, and so on." with "N_1(S)=3, N_2(S)=3^2, N_3(S)=3^3, and so on, where S is Sierpinski's Triangle." 9-27-2004 M Hvidsten 381 17 Replace "about 0.35" with "about 0.3" 9-28-2004 M Hvidsten 381 23 (-4) Replace "about 0.37" with "about 0.3" 9-28-2004 M Hvidsten