Euclid's Fifth

Euclid's Fifth Postulate

Adjust the sliders to change the size of alternate angles n and m. Can you find the relationship between n and m to decide which side of XY the lines AB and CD cross?

New Resources

Perpendicular Lines: Quick Exploration
Pythagorean Template: Integer Legs
Parabolas, Lines and Nomograms
Congruent Figures
What Do You See? (2)

Discover Resources

Recta Tangente a una circunferencia por un punto fuera
Toggle Script
Trig in the unit circle ~ Reference Angles and Symmetry
Disc Action!!!
Stetig aber nicht gleichmässig stetig

Discover Topics

Subtraction
General Quadrilateral
Quadrilaterals
Multiplication
Rational Numbers