Answer:

Step-by-step explanation:
We know

in the third quadrant 
We use a scientific calculator to find the inverse cosine of -0.9041 to find

Since this angle is not in the required quadrant we must find the other angle who has the same cosine. The required angle is equidistant from the found value from the 180 degrees angle, so our solution is

Its adding 9 every time.
-3, 6, 15, 24, 33, 42, 51, 60
8x - 13 = x + 1
Solve for x
Add 13
8x = x + 14
Subtract x
7x = 14, x = 2
Answer: the number is 2
You have to find the angle for it try it!!!!!!!!!!
Size 40 is the cheapest, because the formula to find lowest price of unit is dividing the price by the unit. so 5.49/24≈ 0.23, 8.00/40=0.2, 15.99/64≈ 0.25