Question

Write the equation of a circle with a center at (2.5, –3.5) and a diameter of 12.
Answer

(x + 2.5)2 + (y – 3.5)2 = 12

(x – 2.5)2 + (y + 3.5)2 = 36

(x + 2.5)2 + (y – 3.5)2 = 36

(x – 2.5)2 + (y + 3.5)2 = 144

Answer 1

general form is
(x - a)^2 + (y - b)^2 = r^2

where (a,b) is the center and r = radius

Answer 2

in your case a = 2.5 and b = -3.5 and r , the radius, = half the diameter = 12/2 = 6

Answer 3

if you plug these values into the general equation you'll have it

Answer 4

(x + 2.5)2 + (y – 3.5)2 = 12

Answer 5

no - look at the right hand side of the general equation its r^2 ( or r * r)

if r = 6 what is r*r ?

Answer 6

36! so then (x + 2.5)2 + (y – 3.5)2 = 36 ?

Answer 7

no its
(x - 2.5)(x - (-3.5)) = 36
(x - 2.5)(x + 3.5) = 36

note the double negative giving +3.5

Answer 8

the second option is the correct one