SAT Math Multiple Choice Question 975: Answer and Explanation
The semicircle shown has its center at point Q. If the measure of the central angle of the shaded sector is 160 degrees, what is the value of x in radians?
- A. π20
- B. π12
- C. π9
- D. π6
Correct Answer: C
Category: Additional Topics in Math / Geometry
Strategic Advice: In most cases, it is easier to carry out calculations in degrees, and then convert your answer to radians.
Getting to the Answer: There are 180° in a semicircle (half of 360°). If the central angle of the shaded sector is 160°, then the value of x, in degrees, is 180° - 160° = 20°. To convert this to radians, multiply by the conversion factor that has degrees in the denominator:, which is (C).