Question

A circle is represented by the equation shown below.

(x - 5)^2 + (y + 9)^2 = 144

Which statement is true?

The circle is centered at (-5, -9) and has a diameter of 12.

The circle is centered at (5, -9) and has a radius of 12.

The circle is centered at (5, 9) and has a diameter of 12.

The circle is centered at (5, 9) and has a radius of 12.

Answer 1

@campbell_st

Answer 2

ok... the general form for a circle is

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

and centre at (h, k) and radius r...

you you use this to find the centre and radius of your circle..?

Answer 3

so i substitute the x and y values in to the equation?

Answer 4

nope... just what do you think the value of h is... when you compare the equations..?

Answer 5

h=x value?

Answer 6

no... have a look

(x - h)^2
(x - 5)^2

what is the value of h in your equation?

Answer 7

compare

(x - h)^2 + (y - k)^2 = r^2 general form
(x - 5)^2 + (y + 9)^2 = 144 Your question

any ideas for h, k or r