Question:
Find the equation of a circle with
Centre at the origin and radius 4
Solution:
The general form of the equation of a circle is:
$(x-h)^{2}+(y-k)^{2}=r^{2}$
Where, (h, k) is the centre of the circle.
r is the radius of the circle.
Substituting the centre and radius of the circle in he general form:
$\Rightarrow(x-0)^{2}+(y-0)^{2}=4^{2}$
$\Rightarrow x^{2}+y^{2}=16$
Ans; equation of a circle with. Centre at the origin and radius 4 is:
$x^{2}+y^{2}=16$