Question

Write the equation of a circle with a center at (0, 8) and a radius of 9.
Write the equation of a circle with a center at (-5, -7) and a radius of 3.8.
Write the equation of a circle with a center at (7, 3) and a diameter of 24.
Write the equation of a circle with a center at (4, 1) and a radius of 6.
Write the equation of a circle with a center at (10, 10) and a radius of 12.
Write the equation of a circle with a center at (-3, -4) and a radius of 3.
Write the equation of a circle with a center at (6, 7) and a diameter of 4.

Please explain me how to do these....

Answer 1

@DanielK16

Answer 2

Wouldn't be just easier to learn how to do this yourself? :P

Circle = a set of points that are all the same distance from one fixed point.

you're basically deriving equation of a circle from the distance formula, or pythagorus.

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

where the r is the radius and (h,k) is the center.

Answer 3

so the first question will be 9^2=(x-0)^2 + (y-8)^2 ?
@iambatman

Answer 4

\(\large (x-{\color{brown}{ h}})^2+(y-{\color{blue}{ k}})^2={\color{green}{ r}}^2\qquad
\begin{array}{rllll}
({\color{brown}{ -5}},{\color{blue}{ -7}})\quad {\color{green}{ r}}=3.8\\
({\color{brown}{ 7}},{\color{blue}{ 3}})\quad {\color{green}{ r}}=24\\
({\color{brown}{ 4}},{\color{blue}{ 1}})\quad {\color{green}{ r}}=6\\
({\color{brown}{ 10}},{\color{blue}{ 10}})\quad {\color{green}{ r}}=12\\
({\color{brown}{ -3}},{\color{blue}{ -4}})\quad {\color{green}{ r}}=3\\
({\color{brown}{ 6}},{\color{blue}{ 7}})\quad {\color{green}{ r}}=4\\
\end{array}\)

Answer 5

Got it !! Thank you so much
@jdoe0001 @iambatman