Question

Circle O is represented by the equation (x + 7)^2 + (y + 7)^2 = 16. What is the length of the radius of circle O?

Answer 1

4

Explanation:

The standard form of a circle is:

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

where (h,k) is the center and

r is the radius.

You compare your equation to mine you should see that:

-h=7 implies h=-7

-k=7 implies k=-7

r^2=16 implies r=4 since 4^2=16

The center is (-7,-7).

The radius is 4.

Answer 2

For this case we have that by definition, the equation of a circle in standard or canonical form is given by:

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

Where:

(h, k) is the center

r: It's the radio

We have the following equation:

`(x + 7) ^ 2 + (y + 7) ^ 2 = 16\\(x + 7) ^ 2 + (y + 7) ^ 2 = 4 ^ 2`

Thus, the radius is 4.

Answer:

4