Interior angles in a triangle add up to 180˚. Triangles close triangleA polygon with three straight sides. have three sides, therefore they have three angles. Interior angles in a triangle sum to a ...

Trigonometry close trigonometryThe study of sides and angles in triangles. can be used to find a missing angle in a right-angled triangle when two sides are known. An understanding of the three ...

An exterior angle of a triangle is equal to the sum of the two non-adjacent interior angles. This theorem provides another ...

Setting posts is tricky—you typically need a solid base and a top that is completely level, which is difficult when the base of a post is sitting on an angle. Here's a great tip for obtaining the ...