10 kids total
picking Truman would be 1 out of 10 or 1/10
then there would be 9 kids left so picking Ryan would be 1 out of 9 or 1/9
the probability of picking both would be 1/10 * 1/9 = 1/90
I don't know but I know it is going to be a lot
Answer: 136 is your answer
Step-by-step explanation:

On the unit cirlce, the cosine of an angle is negative whenever the angle falls in the interval

.
If you recall your special triangles, this cosine occurs for angles of

and

.
More generally, this occurs for

and

, where

is an integer.
Answer:
A
Step-by-step explanation:
B, C and D are all equations.
A is the only one that is not.
The answer is A.