# Math Help - circle analytic geometry

1. ## circle analytic geometry

5. A circle is sketched on a coordinate plane with the center at (6, 8). The circle passes through the point (0, 5). Which of these expressions could be used to find r. the radius of the circle

all answers to this question are squared

A. (6 - 0)^2 + (8 - 5)^2
B. (6 + 8)^2 + (0 + 5)^2
C. (6 - 8)^2 + (0 - 5)^2
D. (6 + 0)^2 + (8 + 5)^2

13. The correct graph for the equation (x - 1)^2 + y^2 = 9 is:

A. Pic 1
B. Pic 2
C. Pic 3
D. Pic 4

2. Originally Posted by dgenerationx2
5. A circle is sketched on a coordinate plane with the center at (6, 8). The circle passes through the point (0, 5). Which of these expressions could be used to find r. the radius of the circle

all answers to this question are squared

A. (6 - 0)^2 + (8 - 5)^2
B. (6 + 8)^2 + (0 + 5)^2
C. (6 - 8)^2 + (0 - 5)^2
D. (6 + 0)^2 + (8 + 5)^2

13. The correct graph for the equation (x - 1)^2 + y^2 = 9 is:

A. Pic 1
B. Pic 2
C. Pic 3
D. Pic 4
You've got detailed informations how to do these questions here: http://www.mathhelpforum.com/math-he...482-post2.html

How about going back, read the post and then doing the new questions?

3. ## i don't equations and stuff. I don't know how to do algebra that good. this stuff is

don't get equations and stuff. will never get this stuff. please help. sorry. this is hard to me.

4. Originally Posted by dgenerationx2
5. A circle is sketched on a coordinate plane with the center at (6, 8). The circle passes through the point (0, 5). Which of these expressions could be used to find r. the radius of the circle

Use the distance formula to find the distance from the center (6, 8) to (0, 5) on the circle.

$r^2=(x_2-x_1)^2+(y_2-y_1)^2$

$(0-6)^2+(5-8)^2=r^2$

Answer A is equivalent to what I have written

all answers to this question are squared

A. (6 - 0)^2 + (8 - 5)^2
B. (6 + 8)^2 + (0 + 5)^2
C. (6 - 8)^2 + (0 - 5)^2
D. (6 + 0)^2 + (8 + 5)^2
Originally Posted by dgenerationx2
13. The correct graph for the equation (x - 1)^2 + y^2 = 9 is:

A. Pic 1
B. Pic 2
C. Pic 3
D. Pic 4
The circle has its center at (1, 0) and a radius of 3. That would be Pic 2. That is if Pic 2 is the one second from the left.

5. thanks masters.