Question

The center of a circle is at the origin. An endpoint of a diameter of the circle is at (-3, -4). How long is the diameter of the circle?

Answer 1

The line from the center to the endpoint of a diameter is a radius. Find the length of that line and use \(d = 2r\) to convert it to a diameter.

The formula for the distance between two points \((x_1,y_1)\) and \((x_2,y_2)\) is

\[D = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}\]

If you're thinking that this looks sort of like the Pythagorean theorem, with the hypotenuse being the line between your two points, give yourself a gold star!

Answer 2

so it would be 10?

Answer 3

Indeed it would be!

Answer 4

than you! =)