Question

Write the standard equation of the circle with center (5, −4) and radius 3.

A. (x − 5)2 + (y + 4)2 = 9
B. (x + 5)2 + (y − 4)2 = 9
C. (x + 4)2 + (y − 5)2 = 3
D. (x + 5)2 + (y − 4)2 = 3

Answer 1

A. (x - 5)² + (y + 4)² = 9

General Formulas and Concepts:

Pre-Calculus

Equation of a Circle: (x - h)² + (y - k)² = r²

• (h, k) is center
• r is radius

Explanation:

Step 1: Define

Center (5, -4)

• h = 5
• k = -4

Radius r = 3

Step 2: Write Equation

Substitute variables into general form.

1. Substitute: (x - 5)² + (y + 4)² = 3²
2. Exponents: (x - 5)² + (y + 4)² = 9