## anonymous 4 years ago okay so i still cant solve this, can someone show me the steps please? a (-1,-7) and b(-10,-8) are the endpoints of a diameter of a circle. find the radius of the circle.

1. Mertsj

$d=\sqrt{[-10-(-1)]^2+[-7-(-8)]^2}$

2. Mertsj

$d=\sqrt{81+1}$

3. Mertsj

$d=\sqrt{82}$

4. Mertsj

That is the diameter.

5. Mertsj

divide by 2 to get the radius.

6. Mertsj

$r=\frac{\sqrt{82}}{2}$

7. anonymous

thank you! :)

8. Mertsj

You'd better learn to use the distance formula. It shows up in all sorts of problems.

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