Answer: see proof below
<u>Step-by-step explanation:</u>
Given: cos 330 = 
Use the Double-Angle Identity: cos 2A = 2 cos² A - 1

Proof LHS → RHS:
LHS cos 165
Double-Angle: cos (2 · 165) = 2 cos² 165 - 1
⇒ cos 330 = 2 cos² 165 - 1
⇒ 2 cos² 165 = cos 330 + 1
Given: 

Divide by 2: 

Square root: 
Scratchwork: 

Since cos 165 is in the 2nd Quadrant, the sign is NEGATIVE

LHS = RHS 
To find the measure<span> of the smallest angle of the triangle, we multiply 4 times 10. So, 4 x 10 = 40. Remember, the sum of the angles of a triangle is 180 degrees. Just take what you are given in a problem and try to </span>determine<span> what will make the final angle add up to 180 degrees.</span>
Answer:
each costumer owe $35.40
Step-by-step explanation:
so, u get 247.79÷7 (cuz it is 7 people)
u get 35.40.
to check just get 35.40×7 and u will revice their total.
X=12 because 3 times 12 equals 36. if you divide by 3 on both sides you would be left with that