Answer:
The equation of circle A with radius AC is , or in other words option d.
Step-by-step explanation:
If the radius of this circle is AC, then we can determine the distance between points A ( - 1, 4 ) and C ( - 5,1 ) to come to the length of the radius -
Distance between A and C =
=
= = = 5 units - Which is also the length of the radius of the circle.
So if the radius is given to be 5 in length, knowing that the general equation for a circle is ( where ( h, k ) is the center and r is the radius ) if the radius is 5, , and solution must be option b / option d.
Now if the radius is AC, the center point must be point A ( circle A ). Therefore point ( - 1, 4 ) is the center, and the equation of the circle must be the following -
= - and hence our solution is option d