Question

Write the equation in standard form for the circle with radius 9 centered at the origin

Answer 1

x² + y² = 81

Explanation:

Standard form for the equation of a circle: (x - h)² + (y - k)² = r²

(where (h, k) is the center and r is the radius)

Given:

• radius (r) = 9
• center of circle = (0, 0)

⇒ (x - 0)² + (y - 0)² = 9²

⇒ x² + y² = 81