Outline
CCSS High School: Geometry (Challenges)
This GeoGebra book contains links to a plethora of problems teachers can use to provide challenging enrichment activities for students that excel within the regular curriculum. Many of the problems in this book come from those posted on Twitter by Antonio Gutierrez (https://twitter.com/gogeometry) and Alexander Bogomolny (https://twitter.com/CutTheKnotMath).
Each challenge (and corresponding animation) is mapped to one (or more) of the CCSS High School: Geometry standards.
Table of Contents
HSG.CO.C.9
- Cut-The-Knot-Action (5)!
- Animation 214
- Cut-the-Knot-Action (3)!
- Animation 188
- GoGeometry Action 40!
- Animation 259
- GoGeometry Action 41!
- Animation 260
- GoGeometry Action 58!
- Animation 278
- GoGeometry Action 63!
- GoGeometry Action 65!
- Animation 285
- Concave Quadrilateral Craziness! (GoGeometry Action 80)
- Hexagonal Surprise! (GoGeometry Action 85)
- GoGeometry Action 123!
- GoGeometry Action 143!
- SolveMyMaths Action 2!
- GoGeometry Action 158!
- GoGeometry Action 159!
HSG.CO.C.10
- Medians & Equal Areas!
- Animation 74
- Animation 90
- Euler Line (Informal Investigation)
- Euler Line Generator
- Morley Action!
- Animation 113
- Napoleon Motion!
- Animation 14
- Hexagonal Napoleon Theorem?
- Animation 172
- Viviani Action! (REVAMPED)
- Equilateral Action (1)!
- Animation 91
- Equilateral Action (2)!
- Animation 94
- Equilateral Action (3)!
- Animation 107
- Equilateral Action (4)!
- Animation 108
- Equilateral Triangle and Rectangle (Area Problem)
- Animation 154
- Equal Triangular Areas in a Regular Pentagon
- Animation 194
- NCTM Calendar Problem (11-2-2016)
- Animation 139
- 9 Point Circle Action
- Animation 34
- 9-Point Circle Action (Part 2)
- Animation 106
- 9-Point Circle Action (Part 3A)
- 9-Point Circle (Informal Investigation)
- Animation 71
- 9-Point Circle Action (Part 3B)
- 9-Point Circle Action (Part 4)
- Animation 53
- 9-Point Circle Action (Part 5)
- Animation 115
- Isosceles Triangle: Surprising Theorem!
- Animation 121
- Cut-The-Knot Action !!!
- More Triangle Action!!!
- Animation 163
- Triangle Median & Circles Action!!!
- Animation 164
- Desargues Action!!!
- Animation 209
- GoGeometry Action 10!
- Animation 219
- GoGeometry Action 14!
- Animation 223
- GoGeometry Action 17!
- Animation 228
- GoGeometry Action 18!
- Animation 229
- Cut-The-Knot-Action 8!
- Animation 230
- GoGeometry Action 20!
- Animation 233
- Cut-The-Knot Action 9!
- Animation 234
- Carnot Action! = GoGeometry Action 27!
- Animation 241
- GoGeometry Action 29!
- Animation 244
- GoGeometry Action 30!
- Animation 245
- Incircle + Excircle = GoGeometry Action 31!
- Animation 246
- GoGeometry Action 32!
- Animation 247
- Cut-The-Knot Action 10!
- Animation 248
- GoGeometry Action 34!
- Animation 250
- Cut-The-Knot-Action 12!
- Animation 251
- GoGeometry Action 35!
- Animation 252
- GoGeometry Action 37!
- Animation 254
- GoGeometry Action 38!
- Animation 255
- GoGeometry Action 39!
- Animation 258
- GoGeometry Action 43!
- Animation 263
- GoGeometry Action 44!
- Animation 264
- GoGeometry Action 51!
- Animation 270
- GoGeometry Action 53!
- Animation 272
- Euler Line Surprise! = GoGeometry Action 54
- Animation 273!
- GoGeometry Action 60!
- Animation 280
- Animation 283
- GoGeometry Action 64!
- Animation 284
- GoGeometry Action 66!
- Animation 286
- GoGeometry Action 68!
- Animation 288
- GoGeometry Action 74!
- GoGeometry Action 75!
- GoGeometry Action 76!
- GoGeometry Action 78!
- GoGeometry Action 82!
- GoGeometry Action 83!
- Cut-the-Knot Action 15!
- Equilateral Triangle + Semicircle = ? (GoGeometry Action 88)
- GoGeometry Action 89!
- GoGeometry Action 90!
- GoGeometry Action 91!
- GoGeometry Action 93!
- GoGeometry Action 97!
- GoGeometry Action 101 !
- GoGeometry Action 103!
- GoGeometry Action 104!
- GoGeometry Action 105!
- GoGeometry Action 106!
- GoGeometry Action 107!
- GoGeometry Action 109!
- SolveMyMaths Action 1!
- GoGeometry Action 110!
- GoGeometry Action 112!
- GoGeometry Action 113!
- GoGeometry Action 115!
- GoGeometry Action 117!
- Blanchet Action = GoGeometry Action 118!
- GoGeometry Action 120!
- GoGeometry Action 121!
- GoGeometry Action 124!
- GoGeometry Action 125!
- Cut-The-Knot Action 18!
- Cut-The-Knot Action 19!
- GoGeometry Action 127!
- Incircle Extension = GoGeometry Action 132!
- Incircle Extension 2 = GoGeometry Action 133!
- GoGeometry Action 134!
- GoGeometry Action 135!
- GoGeometry Action 138!
- GoGeometry Action 147!
- GoGeometry Action 152!
- GoGeometry Action 156!
- GoGeometry Action 160!
- Regular Decagon Magic!
- GoGeometry Action 161!
- GoGeometry Action 162!
HSG.CO.C.11
- Finsler-Hadwiger Action!!!
- Animation 110
- Thebault Action!!!
- Animation 83
- Van Aubel Action!!!
- Animation 109
- Square Problem
- 3 Squares Problem
- Animation 120
- Harmonic Mean In an Isosceles Trapezoid
- Square Action! (Proof Problem 1)
- Cut-The-Knot Action (4)!
- Animation 213
- Rhombus Action + Sequel = GoGeometry Action 7!
- Animation 215
- GoGeometry Action 11!
- Animation 220
- GoGeometry Action 12!
- Animation 221
- GoGeometry Action 18!
- Animation 231
- GoGeometry Action 21!
- Animation 235
- GoGeometry Action 22!
- Animation 236
- GoGeometry Action 23!
- Animation 237
- GoGeometry Action 24!
- Animation 238
- GoGeometry Action 36!
- Animation 253
- Cut-the-Knot-Action 13!
- Animation 257
- GoGeometry Action 42!
- Animation 261
- Cut-The-Knot-Action 14!
- Animation 262
- GoGeometry Action 45!
- Animation 265
- GoGeometry Action 46!
- Animation 266
- GoGeometry Action 47!
- Animation 267
- Rhombus Surprise! (GoGeometry Action 57)
- Animation 277
- GoGeometry Action 67!
- Animation 287
- GoGeometry Action 69!
- Square + Rhombus = Constant Surprise! (GoGeometry Action 71)
- GoGeometry Action 73!
- Parallelogram? Why So? (GoGeometry Action 77)
- Square and Quarter Circle Action = GoGeometry Action 81!
- 3 Squares Problem (II)
- GoGeometry Action 94!
- GoGeometry Action 95!
- GoGeometry Action 96!
- GoGeometry Action 98!
- GoGeometry Action 99!
- GoGeometry Action 102 !
- Square + Regular Hexagon Action!
- GoGeometry Action 108!
- GoGeometry Action 114!
- GoGeometry Action 119!
- Cut-The-Knot Action 17!
- GoGeometry Action 126!
- GoGeometry Action 130!
- GoGeometry Action 136!
- GoGeometry Action 139!
- GoGeometry Action 140!
- Parallelogram + 2 Equilateral Triangles: How to Prove?
- GoGeometry Action 153!
HSG.CO.D.12
HSG.C.A.2
- Butterfly Theorem Action!
- Animation 132
- Not Your Everyday Chord & Tangent Theorem
- Animation 133
- Cut-The-Knot Action (2) !!!
- Animation 152
- Int+Ext Tangent Action!
- Animation 155
- Square, Tangent, and Two Congruent & Tangent Circles
- Animation 153
- GoGeometry Action 1!
- Animation 205
- GoGeometry Action 2!
- Animation 206
- GoGeometry Action 3!
- Animation 207
- GoGeometry Action 4!
- Animation 208
- GoGeometry Action 5!
- Animation 210
- GoGeometry Action 6!
- Animation 212
- GoGeometry Action 8!
- Animation 216
- Cut-The-Knot Action (6)!
- Animation 217
- GoGeometry Action 9!
- Animation 218
- GoGeometry Action 13!
- Animation 222
- GoGeometry Action 15!
- Animation 224
- GoGeometry Action 16!
- Animation 226
- Cut-The-Knot Action 7!
- Animation 227
- GoGeometry Action 19!
- Animation 232
- Thales Action + Sequel = GoGeometry Action 25!
- Animation 239
- GoGeometry Action 26!
- Animation 240
- Carnot Action! = GoGeometry Action 27!
- Animation 241
- Incircle + Excircle = GoGeometry Action 31!
- Animation 246
- Cut-The-Knot Action 10!
- Animation 248
- Cut-The-Knot-Action 11!
- Animation 249
- GoGeometry Action 48!
- Animation 268
- GoGeometry Action 49!
- GoGeometry Action 50!
- Animation 269
- GoGeometry Action 52!
- Animation 271
- 60-Degree Sector Surprise! (GoGeometry Action 55)
- Animation 274
- Neusis Logic Action = GoGeometry Action 56!
- Animation 275
- Animation 276
- GoGeometry Action 59!
- Animation 279
- GoGeometry Action 61!
- Animation 281
- GoGeometry Action 62!
- Animation 282
- GoGeometry Action 70!
- GoGeometry Action 72!
- GoGeometry Action 79!
- Geometric Mean Madness! (GoGeometry Action 84)
- Mickey Mouse Theorem! (Cut-the-Knot Action 16)
- More Geometric Mean Action! (GoGeometry Action 86)
- GoGeometry Action 87!
- GoGeometry Action 92!
- A Stronger Conclusion!
- GoGeometry Action 100!
- GoGeometry Action 116!
- GoGeometry Action 122!
- GoGeometry Action 128!
- GoGeometry Action 129!
- GoGeometry Action 131!
- GoGeometry Action 137!
- GoGeometry Action 142!
- Circle Optimization Challenge!
- SolveMyMaths Action 5!
- GoGeometry Action 148!
- Cyclic Quadrilateral: Quick Warm Up (GoGeometry Action 149!)
- Archimedes Insight = GoGeometry Action 150!
- More Archimedes Insight = GoGeometry Action 151!
- GoGeometry Action 154!
- GoGeometry Action 155!
- Archimedes Insight 3: GoGeometry Action 157!
HSG.SRT.B.5
HSG.GPE.A.2
HSG.GPE.A.3
Links to Other CCSS High School: Geometry Standards
Additional - Links to CCSS High School: Functions Resources