Unit 12 Circles in a Coordinate Plane Test Review

The polygon circumscribes a circle. What is the perimeter of the polygon? (a)  

• 78 cm
• 39 cm
• 5320 cm
• 13 cm

Answer explanation

If two tangent segments to a circle share a common endpoint outside the circle, then the two segments are congruent.

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12.1.18

In the figure to the right, if AC = 16 and BC = 13, what is the radius? Round to the nearest tenth. (a)  

• 9.3 units
• 87 units
• 9.2 units
• 3 units

Answer explanation

AB^2 + BC^2 = AC^2

AB^2 + 13^2 = 16^2

AB^2 + 169 = 256

AB^2 = 87

AB = sqrt (87)

AB = 9.327

= 9.3 (rounded to nearest tenth)

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12.1.3

Determine whether a tangent is shown in the diagram. (a)  

• Yes
• No

Answer explanation

Converse of Pythagorean Theorem: The line is tangent to the circle if and only if

5^2 + 15^2 = 16^2.

If 5^2 + 15^2 = 16^2, then yes, there is a tangent to the circle.

If 5^2 + 15^2 does not equal 16^2, then no, there is not a tangent to the circle.

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12.1.15

• 20 degrees

• 40 degrees

• 60 degrees

• 10 degrees

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12.2.1

Find the value of x.

Mathematical Equivalence

ON

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12.2.8

Find the value of x. Round to the nearest tenth. (a)  

• 5.1 units
• 26.2 units
• 74.24 units
• 8.6 units

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12.2.14

Mathematical Equivalence

ON

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12.3.7

What arc does angle F intercept?

• 
• 
• 
• 
• 

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12.3.1

Find the value of each variable. Match the variable to its correct value.

• a

• b

• c

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12.3.13

Find the value of x. Round to the nearest tenth.

• 32

• 3.2

• 12

• 320

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12.4.1