Answer:C) x2 + y2 =45
Step-by-step explanation:
The equation of a circle in standard form is (x-h)2+(y-k)2=r2.
Since you know the center is (0,0), you can sub this is value in for h and k, then use the point (3,6) to sub in for x and y and you will find r2 =45. Hope that helps :)
Answer:
C
Step-by-step explanation:
The equation of a circle centred at the origin is
x² + y² = r² ( where r is the radius )
The radius is the distance from the centre to a point on the circle.
Calculate r using the distance formula
r = √ (x₂ - x₁ )² + (y₂ - y₁ )²
with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (3, 6)
r = [tex]\sqrt{(3-0)^2+(6-0)^2}[/tex]
= [tex]\sqrt{3^2+6^2}[/tex]
= [tex]\sqrt{9+36}[/tex]
= [tex]\sqrt{45}[/tex] ⇒ r² = ([tex]\sqrt{45}[/tex] )² = 45, thus
x² + y² = 45 → C
