Notice you are connecting a relationship of two side measures to an angle measure.

Because not all right triangles have an obvious "short leg"

(For example a 45-45-90)

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We need slightly different names.

Sine is the relationship between an acute angle in a right triangle and...

The ratio of the opposite and hypotenuse sides.

Cosine is the relationship between an acute angle in a right triangle and...

The ratio of the adjacent and hypotenuse sides.

Tangent is the relationship between an acute angle in a right triangle and...

The ratio of the opposite and adjacent sides.

I stubbed my toe on outdoor school and had to soak it in the river.

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< Memorize This

Well, if you are standing on the 25 degree angle what is the side called that is marked 8m?

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How do we use a calculator to find b and c?

The 8m side is "adjacent" to the 25 degree angle, so you must use a trig function with "adjacent" in the ratio.

Hint: SOH CAH TOA

Set up a function and solve:


Tan25= b/8

(Multiply both sides by the denominator)


8*Tan25 = b


Hint: SOH CAH TOA