Which of the following is not a variation of a Pythagorean identity?

Which of the following is a correct Pythagorean trigonometric identity?

In a $\mathrm{circle}$, if two $\mathrm{chords}$ are $\mathrm{congruent}$, what can be said about the $\mathrm{arcs}$ they subtend?

Which of the following correctly expresses the relationship between the length of an arc $s$ of a circle, its radius $r$, and the central angle $\theta$ in radians?

Determine whether each statement is true or false. If false, tell why. See Example 4. cos 60° = 2 cos² 30° - 1

Use identities to correctly complete each sentence.

If cos θ = 0.8 and sin θ = 0.6, then tan(-θ) = ________________.

Find sin θ.

cos θ = 5/6, θ in quadrant I

Find sinθ.

cot θ = -1/3, θ in quadrant IV