## CSETMathGuru: THE Site for Single Subject Math

**What is the trigonometry you need to know for Subtest I?**

While Subtest II and Subtest III involve considerable Trigonometry, Subtest I does, too -- in the topic of vectors.

You ought to be able to

* use sine, cosine and tangent ratios to solve right triangles i.e. find all sides and angles of a right triangle

* know trigonometric ratios of 30-60-90 and 45-45-90 triangles.

This way you shall be able to find the magnitude and direction of a vector, given its horizontal and vertical components; conversely, you shall be able to determine the horizontal and vertical component of a vector, givem its magnitude and direction.