Need urgent asap! trig question 7, 9, 10, 11, 12plz,, plz show step by step work on each one plz!

You need the Unit Circle to answer these questions! (attached)

7.

Step-by-step explanation:

8. 0

Step-by-step explanation:

The sum formula for cos is: cos (A + B) = cosA cosB - sinA sinB

Since we are given cos75° cos15° - sin75° sin15°, we can conclude that we are looking for cos (75° + 15°) = cos 90°.

The Unit Circle shows us that cos 90° = 0

9.

Step-by-step explanation:

The given expression is for tan (A + B).

tan (10° + 20°) = tan 30° =

10.

Step-by-step explanation:

11. TOO BLURRY TO SEE THE PROBLEM

12.

Step-by-step explanation:

Quadrant II means that sin is positive and cos is negative.

the perimeter is increased by a factor of 2

a = 3.14

b = 18

c = 18/5 or 3.6 or 3 3/5

step-by-step explanation: