Question

What is the radius of the circle whose equation is x2+y2=18​

Answer 1

r =
`3√(2)`

Explanation:

equation of a circle:
`(x-a)^2+(y-b)^2=r^2`

where (a, b) is the center and r is the radius

Therefore, for the equation
`x^2+y^2=18`

• a = 0
• b = 0
• r² = 18

⇒ r =
`√(18)` =
`3√(2)`