9.2 Trigonometry Day 1 FLASHCARDS: optional Practice

To find the length of a side using cosine, use the formula: cos(θ) = adjacent/hypotenuse. Rearranging gives: adjacent = hypotenuse * cos(θ).

To find the length of a side using tangent, use the formula: tan(θ) = opposite/adjacent. Rearranging gives: opposite = adjacent * tan(θ).

To find the length of a side using sine, use the formula: sin(θ) = opposite/hypotenuse. Rearranging gives: opposite = hypotenuse * sin(θ).

Using the Pythagorean identity: cos(θ) = sqrt(1 - sin²(θ)) = sqrt(1 - 0.6²) = sqrt(0.64) = 0.8.

The relationship is given by: tan(θ) = sin(θ)/cos(θ).

Using the Pythagorean theorem, opposite = 5 * (3/5) = 3 and adjacent = 5 * (4/5) = 4.

tan(45°) = 1.