Question

geometry question

Answer 1

i can help you

Answer 2

I think it is C

Answer 3

XD theyre not choices

Answer 4

their are look at your question u posted

Answer 5

@dan815

Answer 6

@jim_thompson5910

Answer 7

the center is the midpoint of PQ

Answer 8

to find the midpoint, you average the coordinates

Answer 9

I dont get it so what do I have to do? can I get a formula?

Answer 10

@ganeshie8

Answer 11

check out this page for the formula and examples

http://www.purplemath.com/modules/midpoint.htm

Answer 12

you are adding up the corresponding x coordinates, then dividing by 2

same for the y coordinates

Answer 13

I found the center of the circle is this correct?
(1x+2x/2, y1+y2/2)
(-10+4/2, -2+6/2)
(-6/2, 4/2)
(-3,2)

Answer 14

correct

Answer 15

that's the center of the circle

Answer 16

since it's the midpoint of the diameter

Answer 17

call the center C

Answer 18

the radius is the distance from C to P

or it is the distance from C to Q

Answer 19

alternatively, you can find the distance from P to Q (the length of the diameter)

then divide by 2 to get the radius

Answer 20

to find the distance between two points, use the distance formula

http://cs.selu.edu/~rbyrd/math/distance/

Answer 21

and how do I do that?

Answer 22

did you have a look at that page?

Answer 23

yes i did..

Answer 24

I'm guessing it didn't make much sense?

Answer 25

What is the x coordinate of point P

Answer 26

I got sqrt 233 is that correct?

Answer 27

let me check

Answer 28

it's a bit small

Answer 29

oh wait, hold on

Answer 30

well if you're finding the distance from P to Q, you use the distance formula to get

\[\Large d = \sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2}\]
\[\Large d = \sqrt{(4-(-10))^2+(6-(-2))^2}\]
\[\Large d = \sqrt{(4+10)^2+(6+2)^2}\]
\[\Large d = \sqrt{(14)^2+(8)^2}\]
\[\Large d = \sqrt{196+64}\]
\[\Large d = \sqrt{260}\]
\[\Large d = \sqrt{4*65}\]
\[\Large d = \sqrt{4}*\sqrt{65}\]
\[\Large d = 2\sqrt{65}\]

Answer 31

That's the exact distance between P and Q

So that's exactly how long the diameter is

Answer 32

Cut that in half to get

\[\Large r = \frac{d}{2} = \frac{2\sqrt{65}}{2} = \sqrt{65}\]

Answer 33

So the radius is exactly \(\Large r = \sqrt{65}\) units long

Answer 34

sqrt 65 is the radius!

Answer 35

exactly

Answer 36

so that means

\[\Large r = \sqrt{65}\]

\[\Large r^2 = (\sqrt{65})^2\]

\[\Large r^2 = 65\]

Answer 37

hopefully you see how to use the center and the radius to find the equation

Answer 38

now last... what do they mean (write an equation for the circle)?

Answer 39

hint: the general equation of a circle is

(x-h)^2 + (y - k)^2 = r^2

Answer 40

(h,k) is the center of this general circle
r is the radius of this general circle

Answer 41

so I add in what I got right?

Answer 42

yeah you just plug in the center and radius

Answer 43

do I solve it?

Answer 44

what's the center?

Answer 45

(-3,2)?

Answer 46

so h = -3, k = 2

Answer 47

r^2 = 65 (shown above)

Answer 48

plug all that into the equation and tell me what you get

Answer 49

x^2+9+y^2+4=4,225

Answer 50

Not sure how you got that, you should get

\[\Large (x-h)^2 + (y - k)^2 = r^2\]

\[\Large (x-(-3))^2 + (y - 2)^2 = 65\]

\[\Large (x+3)^2 + (y - 2)^2 = 65\]

Answer 51

Keep in mind that r isn't 65, r^2 = 65

Answer 52

x^2+y^2=52

Answer 53

how are you getting that?

Answer 54

\[\Large (x+3)^2 \neq x^2 + 9\]

Answer 55

also,

\[\Large (y - 2)^2 \neq y^2 + 4\]

Answer 56

you can stop at \[\Large (x+3)^2 + (y - 2)^2 = 65\]

Answer 57

after I got those I added 4 and 9

Answer 58

oh ok well thankyou soooooo much

Answer 59

you're welcome