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

Congruent Figures
Perpendicular Lines: Quick Exploration
Parabolas, Lines and Nomograms
Squaring a Rectangle (PST Version)
Congruent Sides & Angles in △s: Exploration

Discover Resources

Singapore Flyer!
Tangent Circles on a Number Line
Rocket Straw DONT DELETE
Vertical Angles
Atomic Radius Trend Going Down a Group

Discover Topics

Variance
Derivative
Functions
Expected Value
Plane Figures or Shapes