Trignometry Board Kit Trigonometric Board helps to understand functions related to the sides and interior angles of a triangle. Trigonometry is analyzing a right triangle where mathematicians refer to "sine," "cosine" and "tangent" functions . The "sine" is the ratio of the side opposite one of the non-90-degree angles to the triangles hypotenuse; the "cosine" is the ratio of the other side to the hypotenuse; and the "tangent" is the ratio of the triangles two non-hypotenuse sides. This Manipulative helps students to do and discover there ideas..