#### Subhotosh Khan

##### Super Moderator
Staff member
Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

#### tkhunny

##### Moderator
Staff member
Please consider "Completing the Square" for the y-portions.

#### Jomo

##### Elite Member
This is a math help forum where we help students solve their problems. That is this is not site where you drop off your problems and pick up the solutions later. Please follow the posting rules for the site and you'll receive excellent help.

#### pka

##### Elite Member
$$(x-h)^2+(y-k)^2=R^2$$ is a circle that is centred at $$(h,k)$$ that has radius $$R>0$$.
Thus with this problem we have
$$x^2+y^2+16y+k=0\\(x-0)^2+(y+8)^2-64+k=0\\x^2+(y+8)^2=64-k$$
Now we are told that the radius is $$10$$ , so what?

##### New member
$$(x-h)^2+(y-k)^2=R^2$$ is a circle that is centred at $$(h,k)$$ that has radius $$R>0$$.
Thus with this problem we have
$$x^2+y^2+16y+k=0\\(x-0)^2+(y+8)^2-64+k=0\\x^2+(y+8)^2=64-k$$
Now we are told that the radius is $$10$$ , so what?
I need to find answer for c part??????????

#### Subhotosh Khan

##### Super Moderator
Staff member
I need to find answer for c part??????????
Did you calculate the value of k?

#### jonah2.0

##### Junior Member
Beer soaked comment/query follows.
$$(x-h)^2+(y-k)^2=R^2$$ is a circle that is centred at $$(h,k)$$ that has radius $$R>0$$.
Thus with this problem we have
$$x^2+y^2+16y+k=0\\(x-0)^2+(y+8)^2-64+k=0\\x^2+(y+8)^2=64-k$$
Now we are told that the radius is $$10$$ , so what?
I need to find answer for c part??????????
The table's been set up for you.
Food is on the table.
What're you waiting for?

#### Subhotosh Khan

##### Super Moderator
Staff member
Beer soaked comment/query follows.

The table's been set up for you.
Food is on the table.
What're you waiting for?
a spoon!

Staff member
Incorrect!

Here the wrkings

#### Attachments

• 2.3 MB Views: 3
• 2.5 MB Views: 3

#### jonah2.0

##### Junior Member
Beer soaked hint follows.
Here the wrkings
Incorrect as noted in post #12.
Requirement (a) was already worked out for you by pka at post #5.
For requirement (b), you are asked to solve for k.
The problem states that the radius is 10.
You should first determine what the value of k is by equating 64 - k with $$\displaystyle 10^2$$, or solve for k in $$\displaystyle 64 - k = 10^2$$
After you do that, more hints will come your way.

##### New member
tn
Beer soaked hint follows.

Incorrect as noted in post #12.
Requirement (a) was already worked out for you by pka at post #5.
For requirement (b), you are asked to solve for k.
The problem states that the radius is 10.
You should first determine what the value of k is by equating 64 - k with $$\displaystyle 10^2$$, or solve for k in $$\displaystyle 64 - k = 10^2$$
After you do that, more hints will come your way.
tnx got it

#### Jomo

##### Elite Member
I don't think that a spoon is enough. Possibly the OP wants to be spoon fed?