For numbers 2 & 3, refer to figure 1. (1 grid = 1 unit)

2. What is the length of the radius of the circle?
A) 3
B)-3
C) 6
D) -6

3. Which of the following is the equation of the circle?
A) x² - y² = 9
B) x² + y² = 9
C) x² + y² = 81
D) x² + y² + 81 = 0 ​

•The lesson is called: Graphing Equation of a Circle & Problem Solving Involving Circle and Geometric Figures