SAT · Additional Topics in Math · Circles, arcs, and sectors
Question sat-q-00196
Easy Multiple choice No calculator
The question
A circle has radius 9. What is its area, in terms of π?
- 9π
- 18π
- 162π
- 81π
Show answer & worked solution
Answer: 81π
Worked solution. Area of a circle is πr². Here r = 9, so area = π × 9² = 81π.
Why each wrong choice is wrong. Confusing area (πr²) with circumference (2πr) is the dominant error here. The 2πr distractor catches it perfectly.
Test-day tactic. Area scales as the square of the radius; circumference scales linearly. When in doubt, sketch a unit circle and check.
About this question type
Items test the standard circle equation (x − h)² + (y − k)² = r², arc length and sector area as fractions of the full circle, inscribed and central angles, and tangent-chord relationships.
You will see a question shaped like this one on roughly every other official SAT form, typically at an early position in the section, where missing them carries an outsize penalty because the curve assumes everyone in your band gets them right. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.