SOLUTION: how to find the radius of a circle if a 24 cm chord is 9 cm from the center

Algebra ->  Circles -> SOLUTION: how to find the radius of a circle if a 24 cm chord is 9 cm from the center      Log On


   

Question 436021: how to find the radius of a circle if a 24 cm chord is 9 cm from the center
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!



We draw in a radius (in green), label its length R cm:




That's a right triangle and we only need to find its
green hypotenuse R cm which is a radius of the circle.
We just use the Pythagorean theorem:

R² = 9² + 12²

R² = 81 + 144

R² = 225
      ___
 R = Ö225

 R = 15

So the radius is 15 cm.

Edwin