SAT Math: Manipulating the x-Value on a Circle to Find a Positive y-Value

y is a positive real number constant, and x is an angle radian measurement with the restriction . Which of the following changes to x would cause the real number constant to be the opposite sign?

Additional Topics in MathCongruence and similarity
Product TypeSAT Math
SAT MathAdditional Topics in Math
Geometry and Measurement
Test PrepSAT Math