Trigonometric Ratios

Front

What is a trigonometric ratio?

Back

A trigonometric ratio is a ratio of the lengths of two sides of a right triangle. The primary trigonometric ratios are sine, cosine, and tangent.

Front

Define sine in terms of a right triangle.

Back

Sine is the ratio of the length of the opposite side to the length of the hypotenuse.

Front

Define cosine in terms of a right triangle.

Back

Cosine is the ratio of the length of the adjacent side to the length of the hypotenuse.

Front

Define tangent in terms of a right triangle.

Back

Tangent is the ratio of the length of the opposite side to the length of the adjacent side.

Front

What is the formula for finding the sine of an angle?

Back

sin(θ) = Opposite / Hypotenuse.

Front

What is the formula for finding the cosine of an angle?

Back

cos(θ) = Adjacent / Hypotenuse.

Front

What is the formula for finding the tangent of an angle?

Back

tan(θ) = Opposite / Adjacent.

Front

In ΔBCD, if ∠D=90° and ∠B=51°, what is the measure of ∠C?

Back

∠C = 39° (since the angles in a triangle sum to 180°).

Front

If CD = 8.8 feet and you need to find DB using sine, what is the equation?

Back

sin(51°) = DB / 8.8.

Front

How do you find the length of a side using cosine?

Back

Use the formula: Adjacent = Hypotenuse * cos(θ).