Question

What is sin for the given right triangle?

Answer 1

Sin of a right triangle is opposite divided by hypotenuse
in this case, that is 5/8.6 = 0.581395349

you can easily remember the trig functions with this acronym:
SOH-CAH-TOA

S: Sine
O: Opposite
H: Hypotenuse

C: Cosine
A: Adjacent
H: Hypotenuse

T: Tangent
O: Opposite
A: Adjacent