Calculating cos-1 ( is gladly appreciated : ) )

(Assuming you want your answer in radians)

If you want the answer in degrees just multiply your answer in radians by giving you:

.

We can do this since (half the circumference of the unit circle is equivalent to 180 degree rotation).

Step-by-step explanation:

is going to output an angle measurement in .

So we are looking to solve the following equation in that interval:

.

This happens in the second quadrant on the given interval.

The solution to the equation is .

So we are saying that implies since .

Answer is .

12cm

the answer is d