Question: What is the equation of a circle with center at (1, 1) and radius 2?
Options:
Correct Answer: (x - 1)² + (y - 1)² = 4
Solution:
The equation of a circle is (x - h)² + (y - k)² = r². Here, r = 2, so (x - 1)² + (y - 1)² = 2² = 4.