Graphing Circles

Remember that the pattern for circles is  Understanding circles img 1 in which (h, k) is the center of the circle and r is the radius.

To graph a circle....

1. Identify the center point and the radius.

2. Graph the center point.

3. Use the radius to find the point above, below, to the left, and to the right of the center point.

4. Draw in the rest of the circle.

Examples:

1. Graphing circles img 1

First, we must find the center point and radius. The center is (1, -2) and the radius is 2. Next, we'll graph the center point:


Graphing circles img 2


Now, since the radius is 2, we will plot points 2 above, 2 below, 2 to the left, and 2 to the right of the center point.


1. Graphing circles img 18

Finally, we will draw the rest of the circle:


Graphing circles img 3


And we are done. Remember, though, that the center point is not technically part of the answer, as it is not actually part of the circle. A perfectly technical graph would look like this:


Graphing circles img 4


2. Graph Graphing circles img 5
First, identify the center and the radius. Center: (0, 1) Radius = 3

Next we'll graph the center point at (0, 1) and use the radius to draw points above, below, to the left, and to the right.


Graphing circles img 6


Finish by drawing the circle:




Graphing circles img 7


Practice: Graph the following circles

1. Graphing circles img 8

2. Graphing circles img 9

3. Graphing circles img 10

4. Graphing circles img 11

5. Graphing circles img 12

Answers:

Graphing circles img 13

Graphing circles img 14

Graphing circles img 15

Graphing circles img 16

Graphing circles img 17


Related Links:
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Fractions
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