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# Circles on the Coordinate Plane Exercises

### Example 1

Give an equation for the circle with center (6, 8) and radius 12 units.

### Example 2

Give an equation for the circle with center (-3, -25) and radius 169 units.

### Example 3

Give an equation for the circle with center (-22.3, 7.95) and radius 4.4 units.

### Example 4

What are the center and radius of the circle with equation (x – 13)2 + (y + 45)2 = 81?

### Example 5

What are the center and radius of the circle with equation (x + 78)2 + (y + 13)2 = 2?

### Example 6

What are the center and radius of the circle with equation (x + 6)2 + (y – 4.3)2 = 169?

### Example 7

Given the circle with equation (x – 21)2 + (y + 18)2 = 36, is the point (24, -12) in the exterior of the circle, in the interior of the circle, or on the circle?

### Example 8

Given the circle with equation (x + 4)2 + (y – 58)2 = 100, is the point (-14, 60) in the exterior of the circle, in the interior of the circle, or on the circle?

### Example 9

Given the circle with equation (x – 9)2 + (y – 3)2 = 152 , is the point (6, 5) in the exterior of the circle, in the interior of the circle, or on the circle?

### Example 10

Given the circle with equation (x – 101)2 + (y – 45)2 = 612 , is the point (90, 105) in the exterior of the circle, in the interior of the circle, or on the circle?

### Example 11

Find an equation for the line that is tangent to the circle with equation (x – 15)2 + (y + 22)2 = 172 at the point (23, -7).

### Example 12

Find an equation for the line that is tangent to the circle with equation (x + 2)2 + (y + 40)2 = 372 at the point (10, -5).