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 they are equal in length. The angles at the ...

vi) (Motivate) If a side of a triangle is produced, the exterior angle so formed is equal to the sum of the two remote interior angles. 2. Triangles i) (Motivate) Two triangles are congruent if any ...

A nonagon has nine sides and a decagon has ten sides. To understand polygons, a good understanding of other angle rules, including triangles and quadrilaterals can be helpful. The word for the name of ...