12-5 Circles in the Coordinate Plane12-5 Circles in the Coordinate Plane

To write an equation of a circle.To write an equation of a circle.

To find the center and radius of a circle.To find the center and radius of a circle.

12-5 Quiz12-5 QuizThe following questions are to help you The following questions are to help you

decide how well you understood today’s decide how well you understood today’s lesson.lesson.

Be sure to ask if you miss one and don’t Be sure to ask if you miss one and don’t understand why.understand why.

Record the number you get right on your Record the number you get right on your portfolio sheet!portfolio sheet!

A. (x – 7)2 + (y + 3)2 = 16

B. (x – 7)2 + (y – 3)2 = 4

C. (x + 7)2 + (y – 3)2 = 16

D. (x + 3)2 + (y – 7)2 = 16

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2. . 2. . Write the standard equation for the circle.center (–6, 8), that passes through (0, 0)

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A. center (–2, –3); r = 7

B. center (–2, –3); r = 49

C. center (– 2, 3); r = 7

D. center (2, –3); r = 7

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4. 4. A low-wattage radio station can be heard only within a certain distance from the station. On the graph below, the circular region represents that part of the city where the station can be

heard, and the center of the circle represents the location of the station. Which equation represents the boundary for the region where the station can be heard?

O 4 8–4–8 x

4

8

–4

–8

y

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5. 5. Write the standard equation of the circle in the graph.

O 4 8–4–8 x

4

8

–4

–8

y

A. (x – 3)2 + (y + 2)2 = 9

B. (x + 3)2 + (y – 2)2 = 9

C. (x – 3)2 + (y + 2)2 = 3

D. (x + 3)2 + (y – 2)2 = 3

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ASSIGNMENT:ASSIGNMENT:

12-5 p.801-802 12-5 p.801-802 #8-52 even#8-52 even

Be sure to RATE your understanding of the lesson 4-3-2-1-0 after you finish it AND give me one complete sentence as to why you rated yourself that way then summarize what the lesson was about in a couple of complete sentences.