Need explanation for how to find "E"(in the picture attached), and how to calculate "sin".

Answer:
Step-by-step explanation:
E is just that Vertex/Angle.
[tex]sin[/tex] is a measure of an angle.
You should learn SOHCAHTOA
[tex]sin = opposite/hypotenuse\\cos(ine) = adjacent/hypotenuse\\tan(gent)=opposite/adjacent[/tex]
The opposite side is relative to the angle.
In this case, the opposite of E is 20
The hypotenuse is 29
so,
[tex]sin(E)= \frac{20}{29}[/tex]