Find the equation of the circle graphed below.
A) $y ^ { 2 } = x ^ { 2 } + 4$
B) $\quad x ^ { 2 } + y ^ { 2 } = 2$
C) $x ^ { 2 } + y ^ { 2 } = 4$
D) $\quad x ^ { 2 } + y = 4$
E) $\quad x ^ { 2 } + y ^ { 2 } = 1$

Question

Find the equation of the circle graphed below. 
A) $y ^ { 2 } = x ^ { 2 } + 4$ 
B) $\quad x ^ { 2 } + y ^ { 2 } = 2$ 
C) $x ^ { 2 } + y ^ { 2 } = 4$ 
D) $\quad x ^ { 2 } + y = 4$ 
E) $\quad x ^ { 2 } + y ^ { 2 } = 1$

Quizplus · Accepted Answer

The circle appears to have a center at the origin (0,0) and a radius of 2 units. Therefore, using the standard form equation of a circle, we get $x^2+y^2=4$. This matches with choice (C).

Find the Equation of the Circle Graphed Below y2=x2+4y ^ { 2 } = x ^ { 2 } + 4y2=x2+4

Find the Equation of the Circle Graphed Below $y ^ { 2 } = x ^ { 2 } + 4$