Answer :
Equation of a circle is:
(x−h)2+(y−k)2=r2
h is the x-coordinate of the center and k is the y-coordinate of the center. Even though the formula has minus signs, those are positive numbers. If there were plus signs in there, the numbers h and k would actually be negative. Now since you're centered at the origin, that means h and k are 0, so you'd just have this:
x2+y2=r2
Now since your radius is 7, just square it and replace r^2 woth that value :)
Answer:
The equation of a circle is [tex]x^{2} + y ^{2} = 49[/tex] .
Option (B) is correct .
Step-by-step explanation:
The general equation of a circle is given by
[tex](x - h)^{2} + (y - k)^{2} = r^{2}[/tex]
Where (h,k) are the centre of the circle r is the radius of a circle.
As given
The circle is centered at the origin, and the length of its radius is 7.
(h,k) = (0,0)
r² = 49
Put in the equation of a circle.
[tex](x - 0)^{2} + (y - 0)^{2} = 49[/tex]
[tex]x^{2} + y ^{2} = 49[/tex]
Therefore the equation of a circle is [tex]x^{2} + y ^{2} = 49[/tex] .
Option (B) is correct .
