Answer:
x² + y² = 3
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 + (
)² = 1 + 2 = 3 ( take the square root of both sides )
CR = r =
, then
x² + y² = (
)² , that is
x² + y² = 3