# Thecenter and radius of the circle x 2 + y 2 = 9 and sketch the graph of the circle.

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

#### Solutions

Chapter 1.8, Problem 87E
To determine

## To calculate: Thecenter and radius of the circle x2+y2=9 and sketch the graph of the circle.

Expert Solution

The center of the circle is (0,0) and radius is 3 units. The graph of the circle is provided below,

### Explanation of Solution

Given information:

The equation x2+y2=9 .

Formula used:

The standard form of the equation of the circle is (xh)2+(yk)2=r2 , where (h,k) denote the center of the circle and r denote the radius.

Calculation:

Consider the equation x2+y2=9 .

Rewrite the equation as,

(x0)2+(y0)2=32

Recall that the standard form of the equation of the circle is (xh)2+(yk)2=r2 , where (h,k) denote the center of the circle and r denote the radius.

Compare, (xh)2+(yk)2=r2 and (x0)2+(y0)2=32 .

Here, h=0,k=0 and r=3 .

Therefore, center of circle is (0,0) and radius is 3 .

Now, on the Cartesian plane construct a circle with center at origin and radius 3 units.

The graph obtained is provided below,

Thus, the center of the circle is (0,0) and radius is 3 units.

### Have a homework question?

Subscribe to bartleby learn! Ask subject matter experts 30 homework questions each month. Plus, you’ll have access to millions of step-by-step textbook answers!