Question

I really don't get this lesson question:
Which statement is true for the circle?
http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/0800/0800_G8_Q29a.gif
Its center is at the ordered pair of 1 over 2, minus 1, and the radius is minus five over two units.

Its center is at the ordered pair of minus 1 over 2, 1, and the radius is five over two units.

Its center is at the ordered pair of 1 over 2, minus 1, and the radius is five over two units.

Its center is at the ordered pair of minus 1 over 2, 1, and the radius is minus five over two units.

Answer 1

@amistre64

Answer 2

@jim_thompson5910

Answer 3

The link doesn't work

Answer 4

it works on mine

Answer 5

@AccessDenied

Answer 6

This link works for you because it is on a course website and you have to be logged in to view it, do you know how to take a screenshot?

Answer 7

umm i think lemme try

Answer 8

Okay if you need help, reply back with your computer OS(Operating System, Mac or Windows)

Answer 9

Here's the whole thing as pasted from the lesson

Answer 10

a radius is always positive

Answer 11

okay...?

Answer 12

that rules out 2 of your choices

Answer 13

so it's either B or C, but I still don't know which

Answer 14

the (x,y) pair at the center will make the (x-a)^2 and (y-b)^2 terms zero

does that make sense?

Answer 15

not really, no...

Answer 16

usually they say

(x-h)^2 + (y-k)^2 = r^2
and the center is at (h,k) with radius r

Answer 17

how do we get h and k?

Answer 18

so if you see (x- 1/2) that means the x value of the center is +1/2

Answer 19

okay

Answer 20

in this case you match your equation to the "generic" one
match
(x-h)^2 + (y-k)^2 = r^2
(x-1/2)^2 + (y + 1)^2 = 25/4

Answer 21

matching y-k to y+1 you have to rewrite y+1 as y - (-1)
now you see y - k matches y - (-1) and k is -1

Answer 22

or remember that you want the y value that makes (y+1)^2 zero. that would be y= -1

Answer 23

so the Y is -1?

Answer 24

then it's C? Right?

Answer 25

yes.

Answer 26

Thank you soooooo much! I'm going to go write you a testimonial! haha

Answer 27

thank you