if sinθ=2/sqrt5 what is tanθ equal to?

x² = 5 - 4 = 1
x = 1
sin Ө = 2 / √5
cos Ө = 1 / √5
tan Ө = 2

sinθ = 2/√5
cos²θ = 1 - sin²θ = ⅕
cosθ = √(⅕) = √5/5
tanθ = sinθ/cosθ = ⅖

sin(θ) = y/h = 2/sqrt(5)

x^2 + y^2 = h^2
x^2 + 2^2 = 5
x^2 = 1
x = +/- 1

cos(θ) = x/h = +/- 1/sqrt(5)

tan(θ) = sin(θ)/cos(θ) = (2/sqrt(5))/(+/- 1/sqrt(5)) = +/- 2

rules
cos^2 x + sin^2 x = 1
tanx = sinx/cosx