Trigonometric Ratios Consider the triangle given below. 1.The box in the bottom right corner tells us that this is a right triangle. 2.The acute angle at the bottom left corner is labeled as the Greek letter θ.

3.The side opposite the right angle is called the hypotenuse. 4.We will call the side opposite the angle θ opposite. 5.We will call the side adjacent to angle θ adjacent. hypotenuse opposite adjacent

We will use the abbreviations for the sides as given below. hyp opp adj

Basic Trigonometric Ratios The basic trigonometric ratio names are given below along with their abbreviations. These need to be memorized. 1.sine θ = sin θ 2.cosine θ = cos θ 3. tanget θ = tan θ 4.cosecant θ = csc θ 5.secant θ = sec θ 6.cotangent θ = cot θ

Basic Trigonometric Ratios The basic trigonometric ratios are defined as ratios of sides of the right triangle. These need to be memorized. hyp opp adj

Basic Trigonometric Ratios The basic trigonometric ratios are defined as ratios of sides of the right triangle. These need to be memorized. hyp opp adj

Note that the triangle can be in many different positions, and there are two possible acute angles to reference, as illustrated by the following. 3 in 4 in 5 in