Question

20. What is the standard form of the equation of the circle in the graph?

x2 + (y + 4)2 = 16

x2 + (y − 4)2 = 16

x2 + (y + 4)2 = 4

x2 + (y − 4)2 = 4

Answer 1

Choice c is correct.

Explanation:

We have to find the standard form of the circle in the graph.

The general form of equation of circle is:

(x-h)² - (y-k)² = r²

Where (h,k) is the center of circle and r represent the radius of circle.

In the graph, (0,-4) is the center of circle and its radius is 2.

So, the equation of this circle :

x²+(y+4)²=4.

So, the option c is the equation of circle in the graph.

Answer 2

Option 3

Explanation:

The equation of a circle has the following standard form

`(x-a) ^ 2 + (y-b) ^ 2 = r ^ 2`

Where the point (a, b) is the center of the circle and r is the radius.

In the circumference it can be seen that the center is at the point (0, -4) and the radius r = 2.

Therefore the equation of the circumference is:

`(x-0) ^ 2 + (y - (- 4)) ^ 2 = 4`

Finally the equation is:

`x ^ 2 + (y + 4) ^ 2 = 4`

Option 3