# 2/8/17- Introduction to Trigonometry

Warm-Up

Find the values of x, y, z, a, b, c, and d on the diagram shown.

We then worked through the following worksheets/activity:

Intro to Trigonometry

Important take-aways from the above worksheet discussed in class:

The side that is the hypotenuse is never referred to as an “adjacent” side. DO NOT CALL THE HYPOTENUSE ADJACENT! SERIOUSLY! DON’T DO IT!

For 9-14, we need to know how to interpret the statement “The ratio of ___ to ___” as a fraction- the first blank is the top, the second blank goes on the bottom of the fraction. So, if you know the side opposite 30º and the hypotenuse, the ratio of the side opposite 30º to the hypotenuse is 1/2.

On the back, it is important to realize that all of the information given about ratios are in reference to a specific angle. #15 gives information about the ratio of the side opposite 22º to the hypotenuse, so the number .3746 can only be used for that ratio.

See examples gone over in class below:

Notes:

Trigonometric Functions

Trig functions take an input of an angle measure, and give an output of a ratio of sides (usually shown in decimal form).

The three main trig functions are:

Sine (abbreviated as “sin”)- the sine function takes an input of an angle measure, and gives the ratio of the side opposite that input angle to the hypotenuse.

Cosine (abbreviated as “cos”)- the cosine function takes an input of an angle measure, and gives the ratio of the side adjacent to that input angle to the hypotenuse.

Tangent (abbreviated as “tan”)- the tangent function takes an input of an angle measure, and gives the ratio of the side opposite to that input angle to the side adjacent to the input angle.

See picture of notes below, to also get the examples shared:

Trigonometry Practice

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