


TrigonometryFinding the Length of a Side in a Right Angled TriangleIf the angle and the length of a side of a right angled triangle are known we can compute the lengths of the other sides. Example 1Suppose θ = 30º and the opposite side is O = 3. We can make use of the sin θ and Pythagoras Theorem (H^{2} = O^{2} + A^{2}) or the tan θ to find the lengths of the hypotenuse and adjacent sides. For example, Hence
By Pythagoras Theorem,
Alternatively, we can find the adjacent side using the tangent function as follows:
Hence
Exercise 4.<< Inverse Trig Functions  Trigonometry Index  Trigonometric Identities >> 