Key Copy of Geometry Ch 9.7 2020.pdf - Name Date Geometry...

Name_______________________________________ Date_____________________ Geometry Ch 9.7
Equations of Circles
Do Now: complete the square
THE VIDEO USES ( our textbook uses (h, k) ?
𝑐
, ?
𝑐
)
Write the equation of each circle.
1.
center at (–2, 3), radius 5
(𝑋 + 2)
2
+ (? − 3)
2
= 25
2.
center at origin, diameter 4
?
2
+ ?
2
= 4
3.
center at (-2, 4), passes through (-6, 7)
use distance formula to find radius r = 5
(? + 2)
2
+ (? − 4)
2
= 25
4. (? − 1)
2
+ (? − 3)
2
= 9
For each circle with the given equation, state the coordinates of the center and the measure of the radius.
Then graph the equation.
+ = 9 5. (? − 2)
2
(? − 1)
2
(2, 1) r = 3
6. x 2 + y 2 – 8x + 2y = -8
Write the equation in standard form by completing the square.
State the coordinates of the center and the measure of the radius.
Then graph the equation.
(? − 4)
2