Question

This is Geometry: Write an equation of a circle with center (6,-9) and diameter= 2 sqrt of 7

Answer 1

So this is just like the last one you did except you have the diameter instead of the radius. Can you find the radius using the diameter?

Answer 2

no im stupped :(

Answer 3

The diameter is two times the radius.

Answer 4

You aren't stupid. You just have to try.

Answer 5

i am in math i always fail :( in english im really good at it

Answer 6

If you fail it is because you aren't trying. So if the diameter is 2 times the radius, how can you find the radius?

Answer 7

even if i try :( did that once ended up gettting a D :(

Answer 8

You aren't dumb.

Answer 9

:(

Answer 10

So if the diameter is 2 times the radius, and the diameter is 2 times sqrt(7) what is the radius?

Answer 11

4?

Answer 12

No.

Answer 13

\[D = 2(r)\]\[D = 2(\sqrt{7})\]
What is r?

Answer 14

6

Answer 15

Look at what I wrote.. What is different about those two lines?

Answer 16

The only difference is that one had an r and one had a \(\sqrt{7}\)

Answer 17

Doesn't it seem likely that r is \(\sqrt{7}\)

Answer 18

ohhhhhh ok so the radius is 7

Answer 19

No, the radius is the square root of 7.

Answer 20

say its sq 8 it would the r would be sqrt of 8 to?

Answer 21

yes.

Answer 22

D = 2(r)
If someone tells you that D is 2\(\sqrt{8}\) Then you know that r is\(\sqrt{8}\)

Answer 23

oh i get it now

Answer 24

oh ok sounds good

Answer 25

If I tell you D is 10, then 2r = 10 so what is r?

Answer 26

10

Answer 27

no

Answer 28

D = 10

Answer 29

2r = 10

Answer 30

r = ?

Answer 31

2

Answer 32

If 10 is 2 times r, then isn't r half of 10?

Answer 33

half of 10 ?

Answer 34

Ok, lets look at it this way.

If I tell you I'm thinking of a number. And I won't tell you what that number is.. We'll call it r.

Answer 35

oh ok

Answer 36

Now I tell you that if you take my number 'r' and multiply it by 2 you will get 12. Can you tell me what the number I'm thinking of is?

Answer 37

10

Answer 38

2 times 10 is 12?!?!

Answer 39

ooo wait i messed up

Answer 40

its 6

Answer 41

Right! Are you a psychic!?!? How did you know?

Answer 42

i just times 6 and 2 hehe

Answer 43

That's a hard way. You have to guess a lot. Couldn't you just divide 12 by 2?

Answer 44

yea so true

Answer 45

Ok. So lets play the guessing game again.

I'm thinking of a radius. I wont tell you ! It's a secret! Shh..

But I will tell you that the diameter is 64. And that diameter is 2 times my radius. What is my radius?

Answer 46

32

Answer 47

OMG you are a psychic! I knew it!

Answer 48

yaya:D

Answer 49

Just to prove your mental powers we'll do one final one.

I'm thinking of a radius. The diameter (2 times the radius) is \(4\sqrt{3}\). What is the radius?

Answer 50

okay thats a bit harderder

Answer 51

But not too hard.

Answer 52

What does \(4\sqrt{3}\) mean?

Answer 53

the r is 3

Answer 54

No.

Answer 55

It's a bit tricky but I think you can do it.

Answer 56

What does \(4\sqrt{3}\) mean?

Answer 57

4 sqrt of 3

Answer 58

Right. But that _means_ you have four \(\sqrt{3}\) added together. It also _means_ \(4 \times \sqrt{3}\)

Answer 59

So can you figure out what:
\[4\times \sqrt{3}\div 2 =\ ?\]

Answer 60

\[4\times \sqrt{3}\over 2\]

Answer 61

that would be 6 then

Answer 62

no.

Answer 63

\[{4(\sqrt{3}) \over 2} = {4 \over 2}(\sqrt{3})\]

Answer 64

What is 4/2?

Answer 65

oh 2

Answer 66

So what is
\[{4 \over 2}(\sqrt{3})\]

Answer 67

Taking too long.. You must have gotten confused.
If 4/2 IS 2
Then (4/2) times sqrt(3) IS 2 times sqrt(3)

Answer 68

umm a lil

Answer 69

Read what I wrote. Out loud if needed.

Answer 70

Sometimes it helps to hear things than to see them.

Answer 71

oh both 4 and 2 time sq 3

Answer 72

No.

Answer 73

then im confused

Answer 74

4 divided by 2 IS 2.
6 divided by 2 IS 3.

(4 divided by 2) times (sqrt 5) IS 2 times (sqrt 5)
(6 divided by 2) times (sqrt 27) IS 3 times (sqrt 27)

Answer 75

If 4 divided by 2 is exactly the same thing as 2 then any time you see 4 divided by 2 you can just write a 2 there instead.

Answer 76

oh i think answer should be 28=(x+6)sq + (y-9)sq am i correct?

Answer 77

Nope.

Answer 78

Close

Answer 79

does the 6 have to be negative and the nine positive?

Answer 80

yes

Answer 81

Also your radius is wrong.

Answer 82

ok is the answer 7=(x-6) sq + (y+9)sq

Answer 83

Yes

Answer 84

yaya i did it :3

Answer 85

=)

Answer 86

thanks so much for your help

Answer 87

Of course. I suggest that if you get some free time you practice some simple equations. I think if you invest a little time in the areas you need work you will find solving these other problems much much easier.

Answer 88

yea thats true thanks for the advice its very helpful