Finding a circles radius,diameter,... .:Resolved:.

[voidflux]

Hello everyone, I havn't had algebra 2 in awhile and I forgot how to use the distance formula which is: sqrt((x2-x1)^2+(y2-y1)^2));
(x1,y1) and (x2,y2) are points. Given the center and a point on the circle how can i find the distance, radius, circumference, and area? Can someone give me an example of using this formula? Then i'll remeber! Thanks!

[voidflux]

Hello, I thought i understood what was going on, but when i implemented this into C++ it didn't work correctly, so can someone tell me if i'm doing this right?
okay well...
i looked at a website that was explaining the distance formula and circles and its example was this:
Find the radius of a circle, given that the center is at (2, –3) and the point (–1, –2) lies on the circle.
so I typed those points in my program and i got:
this output:

Enter the center of the circle and a point on the circle:
Center's (x and y): 2 -3

Point(x and y): -1 -2
Radius: 3.16228
Diameter: 3.16228
Circumference: 19.8692
Area: 31.416
Press any key to continue

Is this correct?
The Radius is correct, becuase the website had the same result. But i dont know why the diameter is the same as the radius. So I must have messed up there...How do you find the diameter? Now that i think about it. The directions says:
The prgoram shold then output the circle's radius, diameter, circumference, and area. but then it says:
Your program must have at least the following functions:
distance, radius, circumferecne, area. So is distance == diameter? if this is the case...to find the distance(diameter) wouldn't i just multiply the radius by 2?

[bugzpodder]

radius*2=diameter

[voidflux]

Thanks! It works fine now, yay.