Curriculum
Bootcamps
Algebra
Geometry
Numbers & Quantities
Statistics & Probability
Functions
Proofs
More Learning Tools
Intelligent Learning Path
Encyclopedia
Study Tips
Pen & Paper exercises
Excel / GeoGebra recipes
Tutor-on-Demand
All Math
Games
Junior Math
Multiplication Master
Treasure Trail
Wind Surfer
Stack n´load
How long is the lightbulb?
12 cm
13 cm
11 cm
10 cm
Prev.
Check answer
Skip
Help?
