203k views
2 votes
Which point lies on the circle represented by the equation (x + 5)2 + (-9)2 = 82?

A. (0,8)
B. (13,-9)
c. (-5,1)
D. (3,17)

2 Answers

3 votes

Answer:

c

Explanation:

User Ehrhardt
by
4.6k points
2 votes

Answer:

None of the given points lies on the circle.

Explanation:

The circle is represented by the following formula:

(x - xc)² + (y - yc)² = r²

Where (xc,yc) are the coordinates of the center and r is the radius of the circle. In the case we have:

(x+5)² + (y-9)² = 82

If a point belongs to this circumference, then the results of applying the points to the equation should be valid. To test all the points we are going to apply each to the equation as shown below:

A.

(0 + 5)² + (8-9)² = 82

5² + (-1)² = 82

25 + 1 = 82

26 = 82 (invalid)

The point does not lies on the circle.

B.

(13 + 5)² + (-9-9)² = 82

(18)² + (-18)² = 82

324 + 324 = 82

648 = 82 (invalid)

The point does not lies on the circle.

C.

(-5 + 5)² + (1 - 9)² = 82

0² + (-8)² = 82

64 = 82 (invalid)

The point does not lies on the circle.

D.

(3 + 5)² + (17-9)² = 82

8² + 8² = 82

64 + 64 = 82

128 = 82 (invalid)

The point does not lies on the circle.

User Marco Rehmer
by
4.1k points