What is the exact value of cos 150°

-√3/2

Step-by-step explanation:

Since our angle is greater than 90, it lies in the second quadrant.

150 is obtuse angle as it is greater than 90.

We know that 150° = 180° - 30°

Also, cos(180-x) = -cos(x) because cosx is negative in the second quadrant.

cos(30) = √3/2

cos(150) = cos(180 - 30) = -cos(30) = -√3/2

OR

It can be written as:-

cos(150) = sin(90 - 150) = sin(-60) = -sin(60) = -√3/2.

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation:

step-by-step explanation:

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