Answer:

Step-by-step explanation:
To write a circle in standard form, expand the equation of the circle and move all terms to one side.

Answer:
These are both 20 so that means that this is proportional, yes.
Step-by-step explanation:
Hi.
To figure this out we can do something called cross multiplying to find a cross product. If we do this and our two answers are equal then it is indeed a proportion.
Here is how we do this.

So basically what we are doing is multiplying across in a diagonal direction.
Diagonal meaning like a slash / .
So in this case we would multiply the 4 and the 5 , since they're diagonal from each other.
Do the same for the 2 and the 10.
So we have to multiply :
4 x 5
2 x 10
=
20
These are both 20 so that means that this is proportional, yes.
Hope this helps.
If you have any questions or concerns feel free to message me.
Answer:
Rational numbers are the numbers that can be expressed in the form of a ratio (P/Q & Q≠0) and irrational numbers cannot be expressed as a fraction
Step-by-step explanation:
The center is at (0,0) so the equation will be like
x^2 + y^2 = r^2 where r = radius of the circle.
from the diagram you can see that r = 4
answer is x^2 + y^2 = 16