SOLUTION: A 48 inch chord is 8 inches closer to the center of a circle then a 40 inch chord. Find the radius of the circle. Please

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Question 1035544: A 48 inch chord is 8 inches closer to the center of a circle then a 40 inch chord. Find the radius of the circle. Please
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!

This is not drawn to scale because the chords would be too
close together if it were.  Also nothing is lost by drawing 
the two chords parallel.



We draw in two radii, and a black line bisecting both
triangles into two right triangles. We label the
part of the part of the black line below the 8 as x.
We label the blue and red radii as r. 



We apply the Pythagorean theorem to the
two right triangles and we have this system
of two equations:



system%28400%2B%2864%2B16x%2Bx%5E2%29=r%5E2%2C%0D%0A576%2Bx%5E2=r%5E2%29

system%28400%2B64%2B16x%2Bx%5E2=r%5E2%2C%0D%0A576%2Bx%5E2=r%5E2%29

system%28464%2B16x%2Bx%5E2=r%5E2%2C%0D%0A576%2Bx%5E2=r%5E2%29

Since both left sides equal r2,

464%2B16x%2Bx%5E2=576%2Bx%5E2

464%2B16x=576

16x=112

x=7

Substitute in

576%2Bx%5E2=r%5E2

576%2B7%5E2=r%5E2

576%2B49=r%5E2

625=r%5E2

%22%22+%2B-+sqrt%28625%29=r

%22%22+%2B-25=r

Ignore the negative value:

25=r

Edwin