Hello!
The angle of 30º is one of the remarkable angles (the others are 45º and 60º).
These angles are the most used in trigonometry, so it's good to memorize it.
Below, I'll explain to you one way to memorize it as a table:
For the sine and cosine, let's fill these spaces with 1 2 3 on the first line, and 3 2 1 on the second line. Then we're going to divide all of that by 2.
When the numerator is 2 or 3 we will put a square root in it.
For the tangent, it will be a little different:
• Tangent of ,30º ,is √3/3
,
• Tangent of ,45º ,is 1
,
• Tangent of ,60º ,is √3
So, the final answers for your exercise are:
Sin 30º: 1/2 or 0.5
Cos 30º: √3/2
Tan 30º: √3/3