Graph x2 + y2 = 9. what are its lines of symmetry?

It has infinitely many line of symmetry. All diameters are line of symmetry.

Step-by-step explanation:

Given: Equation is x² + y² = 9

To find: line of symmetry of given equation

Given equation is the equation of circle.

x² + y² = 9

re write,

(x-0)² + (y-0)² = 3²

by comparing given equation with standard equation of circle ,

(x-h)² + (y-k)² = r²

we get, h = 0 , k = 0 , r = 3

⇒ Centre of circle = ( 0 , 0 ) and radius of circle = 3 unit

Since It is a circle. so it has Infinitely many line of symmetry

Also, All diameters of this circle are line of symmetry for this circle.

Some equation of line of symmetry,

x-axis : y = 0

y-axis : x = 0

linear pair postulates