SAT Math Multiple Choice Question 970: Answer and Explanation
Question: 970If the area of a circle is 64π, what is the circumference of the circle?
- A. 8π
- B. 16π
- C. 32π
- D. 64π
Correct Answer: B
Category: Additional Topics in Math / Geometry
Strategic Advice: The key to answering circle questions is often in finding the length of the radius. Make that the first thing you look for.
Getting to the Answer: The area of a circle is given by A = πr2. Substitute the given area (64π) into the formula to get 64π = πr2, which simplifies to r = 8. The circumference of a circle is equal to 2πr, so the circumference of this particular circle is 2π × 8 = 16π. Therefore, (B) is correct.