Home Geometry Theorems Pythagoras Euclid's Elements Book II, 12: Law of Cosines Heron's Formula Median length, Apollonius' Theorem Menelaus Ceva
  Ptolemy Nine-Point Circle, Euler Line More

Euclidean Geometry

Classical Pythagorean Theorem

Pythagorean Theorem.

Euclid's Elements, Book II, Proposition 12

Euclid's Elements Book II, Proposition 12: Law of Cosines.

Euclid's Elements: Book II, Proposition 13: Law of Cosines

Euclid's Elements Book II, Proposition 13: Law of Cosines.

Median Length theorem

Median length, Apollonius' Theorem

Geometry Problem 889

Carnot's Theorem. Geometry Problem 889
Carnot's Theorem in an acute triangle, Circumcenter, Circumradius, Inradius. GeoGebra, HTML5 Animation for Tablets.

Ceva's Theorem

Ceva's Theorem. Concurrency. Interactive proof with animation. Key concept: Menelaus Theorem. 

In its broad sense, education refers to any act or experience that has a formative effect on the mind, character, or physical ability of an individual...In its technical sense education is the process by which society, through schools, colleges, universities, and other institutions, deliberately transmits its cultural heritage--its accumulated knowledge, values, and skills--from one generation to another. George F. Kneller, Introduction to the Philosophy of Education (New York: John Wiley and Sons, 1971.) 

  Recent Additions