What is the equation of the circle?

Answer:
x² + y² = 3
Step-by-step explanation:
The equation of a circle centred at the origin is
x² + y² = r² ( where r is the radius )
Using Pythagoras' identity in right triangle CRT
CR² = 1² + ([tex]\sqrt{2}[/tex] )² = 1 + 2 = 3 ( take the square root of both sides )
CR = r = [tex]\sqrt{3}[/tex] , then
x² + y² = ([tex]\sqrt{3}[/tex] )² , that is
x² + y² = 3