Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 8 - No. 9)

Which of the following equations is equivalent to cos(θ) = Adjacent / Hypotenuse?

θ = cos^-1(Adjacent / Hypotenuse)

θ = sin^-1(Adjacent / Hypotenuse)

θ = tan^-1(Adjacent / Hypotenuse)

θ = cos(Hypotenuse / Adjacent)

The inverse cosine function is used to find the angle when the cosine ratio is known.