Circles

Formulas/Basics

100

What is the point of the origin?

(0,0)

200

What's another phrase for center radius form?

Standard Form

300

What is the formula for Center Radius Form?

(x-h)^2+(y-k)^2=r^2

400

What is the formula for General form?

x^2+y^2+Ax+By+C=0

500

What's the second step for converting from CRF to general form?

Combine Like Terms

Find the Center

100

What is the center point of (x-7)^2+(y-3)^2

(7,3)

200

What is the center point of (x+8)^2+(y-3)^2

(-8,3)

300

What is the center point of (x-5)^2+(y-5)^2

(5,5)

400

What is the center point of (x-6)^2-(y+2)^2

(6,-2)

500

What is the center point of (x+2)^2+(y-2)^2

(-2,2)

Convert to General Form

100

What is (9x-1)^2+(y+2)^2=4

x^2+-2x+1+y^2+4y+4=4

200

What is (x+1)^2+(y-2)^2=16

x^2+y^2+2x-4y-9=0

300

What is (x-5)^2+(y+3)^2=81

x^2+y^2-10x+6y-47=0

400

What is (x-1)^2+(y-2)^2=16

x^2+y^2-2x-4y-9=0

500

What is x^2+y^2-9

x^2+y^2-9=0

Fix the equation

100

(x-7)^2+(y+2)^2=16 C=(-7, 2) R=4

(x+7)^2+(y-2)^2=16

200

(x-7)^2+(y-3)^2=9 C=(-7,3) R= 3

(x+7)^2+(y-3)^2=9

300

(x-1)^2+(y+8)^2=81 C= (5,6) R=9

(x-5)^2+(y-6)^2=81

400

(x-5)^2+(y+5)^2=81 c= (5,-5) R=6

(x-5)^2+(y+5)^2=36

500

(x-4)+(y-6)=4 C= (4,6) R=2

(x-4)^2+(y-6)^2=4

Misc.

100

You can graph a circle by using how many points?

5 points

200

What is the number the arrow is pointing to represent? (x-1)^2+(y+2)^2=4 ^

X-value

300

What is the number the arrow is pointing to represent? (x-1)^2+(y+2)^2=4 ^

Y-value

400

What is the number that the arrow is pointing to? 9x-1)^2+(y+2)^2=4 ^

The radius

500

Convert this to Center Radius Form: x^2+-2x+1+y^2+4y+4=4

(x-1)^2+(y+2)^2=4