Question

question 22 of 25

the graph of the equation below is a circle. what is the length of the radius of the circle?

\\((x + 5)^2 + (y + 7)^2 = 21^2\\)

a. 10.5
b. 441
c. 42
d. 21

Explanation:

Identify the standard form of a circle equation

$$ (x - h)^2 + (y - k)^2 = r^2 $$

Compare the given equation to the standard form

$$ (x + 5)^2 + (y + 7)^2 = 21^2 \implies r^2 = 21^2 $$

Solve for the radius

$$ r = 21 $$

Answer:

• (A) 10.5
• (B) 441
• (C) 42
• (D) 21 (Correct answer)