Circles

What is the formula for circumference of a circle given the diameter?

• C = π r
• C = 2 π r
• C = π d
• C = 2 π d

If the circumference of a circle is 22 π ft, what is the radius?

• 22 ft
• 11ft
• π ft
• no ft

What is the standard equation of a circle?

• (x-k)² + (y-h)² = r²

• (x+h)² + (y+k)² = r²

• (x-h)² + (y-k)² = r²

• (k-x)² + (h-y)² = r²

What is the center and the radius of the circle with equation, (x-4)² + (y-2)² = 25

• Center is (5,2) and radius is 4.

• Center is (2,5) and radius is 4

• Center is (2,4) and radius is 5

• Center is (4, 2) and radius is 5

What is the center and radius of a circle with an equation (x+5)² + (y-1)² = 64

• Center is (5,1) and radius is 8

• Center is (-5, 1) and radius is 8

• Center is (-1, 5) and radius is 8

• Center is (-5,-1) and radius is 8

Which equation matches the circle on the graph?

• (x-2)²+(y+3)²=81

• (x+3)²+(y-2)²=9

• (x-2)²+(y+3)²=9

• (x+3)²+(y-2)²=3

Which equation matches the circle on the graph?

• (x-3)²+(y-4)²=16

• (x-5)²+(y-2)²=20

• (x+3)²+(y+4)²=16

• (x-9)²+(y-16)²=32

What is 5π/6 radians in degrees?

• 180
• 150
• 360
• 120

What is 7π/4 radians in degrees?

• 300
• 135
• 315
• 45

What is 45 degrees in radians?

• π/2
• π/6
• π/4
• 3π/4