Triangle Angle Theorems

Look at the roof of a house, the truss of a bridge, or the frame of a bicycle — you will find triangles everywhere, because a triangle is the one shape that cannot be pushed out of form. To design and check these structures, engineers rely on a handful of simple, unshakeable facts about the angles inside a triangle and about when two triangles are truly identical. In this lesson you learn those facts, and from that point on almost every geometry problem in your O/L paper becomes a matter of applying the right rule with confidence.