Simplify the following text for a Grade 8 native English-speaking person.
Original: For example , a circle of radius 2 may be described as the set of all points whose coordinates x and y satisfy the equation x2 + y2 = 4 .
Simplified: For example , the circle of radius 2 may be described by the equation xÂ + yÂ = 4 ( see Figure 2 ) .