Question

Robert has graphed the following equation, which has generated a circle: (x + 3)2 + (y - 7)2 = 81. What is the radius of this circle?

Answer 1

Answer:-

Equation of circle : (x +3)² + (y-7)² = 81

General equation of circle :-- (x - h) ² +(y- k)² = r²

• h = -3
• k = 7
• r = 9

Radius of circle ⭕ is 9

Answer 2

Answer:

Given equation is

» (x + 3)² + (y - 7)² = 81

On comparing with general equation of circle.

» (x - h)² + (y - k)² = a²

We get, a² = 81

» Therefore, Radius = 9 units