A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. (The dashes on the lines show which are equal in length.) The angles at the ...

Parallel lines are indicated by arrows going in the same direction. Parallel lines are indicated by arrows going in the same direction. If there is more than one set of parallel lines in a diagram, ...

Everyone learns the number one rule about triangles in high school: the angles of a triangle add up to 180 degrees. But did you know that sometimes they don't? Triangles are much more interesting than ...