Question

Which of the following is the equation of a circle whose center is at the origin and whose radius is 4?

x^2+y^2=2
x^2+y^2=4
x^2+Y^2=16

Answer 1

x^2 + y^2 = 16

Explanation:

Answer 2

`\bf \textit{equation of a circle}\\\\ (x- h)^2+(y- k)^2= r^2 \qquad center~~(\stackrel{0}{ h},\stackrel{0}{ k})\qquad \qquad radius=\stackrel{4}{ r} \\\\\\ (x-0)^2+(y-0)^2=4^2\implies x^2+y^2=16`