Think & Click: Graphs of Circles

Now, you try. Complete the Think & Click activity by looking at each problem below, thinking about it, and then clicking on the question to reveal the solution.

Graph the circle defined by (x – 2)² + (y – 1)² = 16
 

C (2,1)
r = 4;

Circle with center at (2,1) and radius 4

 

Graph the circle defined by (x + 1)² + y² = 4
 

C (-1, 0)
r = 2;

Circle with center at (-1, 0) and radius 2

 

Graph the circle defined by (x – 3)² + (y – 4)² = 12
 

C (3, 4)
r =

Circle with center at (3, 4) and radius square root of 12

 

What is the equation of the following circle?

Circle with center at (0, -2) and radius 5

 

C (0, -2)
r = 5
x² + (y + 2)² = 25
 

Graph the circle with a diameter of 8 and center at the point (-2, -1). What is the equation of this graph?
 

C (-2, -1)
r =

Circle with center at (-2, -1) and radius 4

(x + 2)² + (y + 1)² = 16