angle sum/difference Identities

Only using angles available on the unit circle, find the set of angles that will add or subtract to the given angle:
$$15\degree$$  

Only using angles available on the unit circle, find the set of angles that will add or subtract to the given angle:
 $75\degree$ 

Only using angles available on the unit circle, find the set of angles that will add or subtract to the given angle:
$$165\degree$$  

Only using angles available on the unit circle, find the set of angles that will add or subtract to the given angle:
$$105\degree$$  

Only using angles available on the unit circle, find the set of angles that will add or subtract to the given angle:
$$255\degree$$  

Use a sum or difference identity to find the EXACT value:

$$\sin\left(15\degree\right)$$  

Use a sum or difference identity to find the EXACT value:
$$\sin\left(75\degree\right)$$  

Use a sum or difference identity to find the EXACT value:
$$\cos\left(75\degree\right)$$  

Use a sum or difference identity to find the EXACT value:

$$\cos\left(105\degree\right)$$

Use a sum or difference identity to find the EXACT value:

$$\cos\left(\frac{\pi}{12}\right)$$