Posted by Emily on .
It says:
Find the area of a rectangle with length 12 inscribed in a circle with radius 7.5.
I know when they're talking about a radius with a figure, they're talking about the length between the center of the circle to a corner of the figure. But that usually works only with a regular figure, and a rectangle isn't one.
Does anyone have any ideas on how to solve it?

math (geometry) 
Ms. Sue,
Since the radius is 7.5, then the diameter is 15. Doesn't that make your rectangle 12 by 15?

math (geometry) 
Emily,
Oh wait! I see where you're getting at. I think since the diameter of the circle is 15, it will make a diagonal within the rectangle to make a right triangle. Therefore, the dimensions of the rectangle are 12 by 9.
Thanks soooooo much, Ms. Sue! You helped me a lot. (the diameter thing got me going! lol) 
math (geometry) 
Ms. Sue,
You're very welcome. :)

math (geometry) 
kidist,
since the radius is 7.5 the diameter will be 15 units.
from the pythagoras theorem Dsqaure=12Square + XSquare, where x= the unknown quantity.
Therfore; x= Root of((15x15)  (12x12)) = 9
Thank you!