6. the answer is 4. because u find the diameter by dividing by 2.
7. answer = 8 , the radius is 4 . so u need to multiply 2 times 4. 2 times 4 =8.
Answer:

Step-by-step explanation:
A circumference of a circle can be determined by this: 2*pi*r
We're given the diameter. Divide that by 2 to get the radius.
6.45/2 = 3.225
Now multiply that by 2*pi. That gives us 2 * 3.14 * 3.225 = 20.253.
This could've also been done easier by doing pi*d where d is the diameter and you give the answer by multiplying them both. Also works, but the above formula is just key to many things and can also be used to derive the simpler one. Hope it helps! :)
You want to isolate C, so the first step would to have it be positive. You would do this by adding C to both sides of the equation to cancel the C on one of the sides out like this:

. Then you want to cancel out the P, so you subtract it on both sides like this:

And that is your answer
Let's look at our equation,
<span>p÷7
We must look at all our options before selecting one of them.
Can the answer be A?
</span><span>Jayna does not know how many pages she needs to read. She knows she has already read for 7 days.
</span><span>
No that would not work,
We would have subtraction. It would look like this.
p-7.
How about B?
</span><span>Jayna does not know how many pages she needs to read. She knows that she has 7 days to finish her book.
</span><span>
That would actually work. This is how our equation would look.
p</span>÷7.
<span>It matches the expression.
Before we make that our final answer, we should check everything else.
Here is C
</span><span>C.
Jayna does not know how many days she has to finish reading. She knows she has to read 7 more pages.
</span>
That would not work.
How about D?
<span>D.
Jayna does not know how many pages she has already read. She knows she has to read 7 more.
</span>
D is also incorrect. It would not work at all.
That means our final answer is:
<span>B.
Jayna does not know how many pages she needs to read. She knows that she has 7 days to finish her book.
</span>
I hope that helped! :)