WHAT I KNOW: Circles

What is the coordinate of the center of a circle O?

• (4, -3)

• (4,3)

• (-3,4)

•   (-3, -4)

How long is the radius of the given circle?

• r = 3

• r = 4

• r = 5

• r = 6

Which graph of a circle below represent the equation 𝑥² + 𝑦² = 1?

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Given circle O below, what is the equation of a circle that describes the given circle?

• 𝑥² + 𝑦² = 4

• 𝑥² + 𝑦² = 8

• 𝑥² + 𝑦² = 16

• 𝑥² + 𝑦² = 25

Which graph of a circle below represent the equation 𝑥² + 𝑦² = 4?

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What are the coordinates of the midpoint of a segment whose endpoints are 

     (-5, 2) and (9, 12)?

• (7, 5)

• (2, 7)

• (-7, 5)

• (7, 2)

What is the distance between the points M (5, 7) and N (5, -4)?

           

• 9

• 10

• 11

• 12

A radio signal can transmit messages up to a distance of 5 km.  If the radio signal’s origin is located at a point whose coordinates are (-2, 7), what is the equation of the circle that defines the boundary up to which the messages can be transmitted?

• (𝑥 − 2)² + (𝑦 + 7)² = 25   

• (𝑥 + 2)² + (𝑦 − 7)² = 5

• (𝑥 + 2)² + (𝑦 − 7)² = 25

• (𝑥 − 2)² + (𝑦 + 7)² = 5

Which of the following equation describes a circle on the coordinates plane with a center at (2, -3) and a radius of 5 units? 

• (𝑥 − 2)² + (𝑦 + 3)² = 25²

• (𝑥 − 2)² + (𝑦 + 3)² = 5²

• (𝑥 − 3)² + (𝑦 + 2)² = 25²

• (𝑥 + 2)² + (𝑦 − 3)² = 5²

The line segment joining ( -10, 2) and (6, 10) is a diameter.  What is its length?

• 16

• 20