Question

Help please???
What is the equation of a circle with a center at (0, 9) and a radius of 9?

Answer 1

(x-0)² + (y-9)² = 9²

Answer 2

then you need to simplify

Answer 3

Similar Example:

Let's say we ask "what is the equation of the circle with radius 4 and center (-2,3)?"


Center: \(\large ({\color{red}{h}},{\color{blue}{k}}) = ({\color{red}{-2}},{\color{blue}{3}})\)
Radius: \(\large r = {\color{green}{4}}\)

Plug all this into
\[\Large (x-{\color{red}{h}})^2+(y-{\color{blue}{k}})^2 = {\color{green}{r}}^2\]
to get
\[\Large (x-{\color{red}{h}})^2+(y-{\color{blue}{k}})^2 = {\color{green}{r}}^2\]
\[\Large (x-({\color{red}{-2}}))^2+(y-{\color{blue}{3}})^2 = {\color{green}{4}}^2\]
\[\Large (x+2)^2+(y-3)^2 = 16\]

Answer 4

okay so the answer is x^2+(y-9)^2=9^2?

Answer 5

you can simplify the 9^2 part

Answer 6

okay so x^2+(y-9)^2=81?

Answer 7

correct

Answer 8

Good job do you understand though?